Morphoproteomic evidence of constitutively activated and overexpressed mTOR pathway in cervical squamous carcinoma and high grade squamous intraepithelial lesions.

Human papilloma virus (HPV) infection of the uterine cervix is linked to the pathogenesis of cervical cancer. Preclinical in vitro and in vivo studies using HPV-containing human cervical carcinoma cell lines have shown that the mammalian target of rapamycin (mTOR) inhibitor, rapamycin, and epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor, erlotinib, can induce growth delay of xenografts. Activation of Akt and mTOR are also observed in cervical squamous cell carcinoma and, the expression of phosphorylated mTOR was reported to serve as a marker to predict response to chemotherapy and survival of cervical cancer patients. Therefore, we investigated: a) the expression level of EGFR in cervical squamous cell carcinoma (SCC) and high-grade squamous intraepithelial lesions (HSIL) versus non-neoplastic cervical squamous epithelium; b) the state of activation of the mTOR pathway in these same tissues; and c) any impact of these signal transduction molecules on cell cycle. Formalin-fixed paraffin-embedded tissue microarray blocks containing 20 samples each of normal cervix, HSIL and invasive SCC, derived from a total of 60 cases of cervical biopsies and cervical conizations were examined. Immunohistochemistry was utilized to detect the following antigens: EGFR; mTOR pathway markers, phosphorylated (p)-mTOR (Ser2448) and p-p70S6K (Thr389); and cell cycle associated proteins, Ki-67 and S phase kinase-associated protein (Skp)2. Protein compartmentalization and expression were quantified in regard to proportion (0-100%) and intensity (0-3+). Mitotic index (MI) was also assessed. An expression index (EI) for pmTOR, p-p70S6K and EGFR, respectively was calculated by taking the product of intensity score and proportion of positively staining cells. We found that plasmalemmal EGFR expression was limited to the basal/parabasal cells (2-3+, EI = 67) in normal cervical epithelium (NL), but was diffusely positive in all HSIL (EI = 237) and SCC (EI 226). The pattern of cytoplasmic p-mTOR and nuclear p-p70S6K expression was similar to that of EGFR; all showed a significantly increased EI in HSIL/SCC versus NL (p<0.02). Nuclear translocation of p-mTOR was observed in all SCC lesions (EI = 202) and was significantly increased versus both HSIL (EI = 89) and NL (EI = 54) with p<0.015 and p<0.0001, respectively. Concomitant increases in MI and proportion of nuclear Ki-67 and Skp2 expression were noted in HSIL and SCC. In conclusion, morphoproteomic analysis reveals constitutive activation and overexpression of the mTOR pathway in HSIL and SCC as evidenced by: increased nuclear translocation of pmTOR and p-p70S6K, phosphorylated at putative sites of activation, Ser2448 and Thr389, respectively; correlative overexpression of the upstream signal transducer, EGFR, and increases in cell cycle correlates, Skp2 and mitotic indices. These results suggest that the mTOR pathway plays a key role in cervical carcinogenesis and targeted therapies may be developed for SCC as well as its precursor lesion, HSIL.

Evidence for the involvement of proximal chromosome 3P loci in the progression of Von Hippel-Lindau related tumors

Von Hippel-Lindau (VHL) disease is an autosomal dominant disorder characterized by the development of retinal and central nervous system hemangioblastoma, renal cell carcinoma (RCC), pheochromocytoma and pancreatic islet cell tumors (PICT). The VHL gene maps to chromosome 3p25 and has been shown to be mutated in 57% of sporadic cases of RCC, implicating VHL in the genesis of RCC. We report a multigeneration VHL kindred in which four affected female siblings developed PICT at early ages. Analysis of the three coding exons of the VHL gene in this family revealed a single, missense mutation in codon 238. Inheritance of the 238 mutation has been reported to correlate with a 62% risk of pheochromocytoma development. In this kindred, all affected individuals carried the mutation as well as one additional sibling who showed no evidence of disease. Clinical screening of this individual indicated small ($<$1 cm) pancreatic and kidney tumors. Results suggest that inheritance of the codon 238 mutation does not correlate with early onset pheochromocytoma. Rather, the only individual in the pedigree with pheochromocytoma was the proband's mother who developed bilateral pheochromocytoma at the age of 62. Thus, the VHL codon 238 mutation may predispose to late onset pheochromocytoma in this family; however, it does not explain the preponderance of PICT in the third generation since this mutation has not been reported to increase the risk of developing pancreatic lesions. This suggests that inheritance of the codon 238 mutation and subsequent somatic inactivation of the wild type allele of the VHL gene may not be sufficient to explain the initiation and subsequent progression to malignancy in VHL-associated neoplasms. Since the two tumor types that most frequently progress to malignancy are RCC and PICT, we asked whether loss of heterozygosity (LOH) could be detected proximal to the VHL gene on chromosome 3 in distinct regions of 3p previously implicated by LOH and cytogenetic studies to contain tumor suppressor loci for RCC. LOH was performed on high molecular weight DNA isolated from peripheral blood and frozen tumor tissue of family members using microsatellite markers spanning 3p. Results indicated LOH for all informative 3p loci in tumor tissue from affected individuals with PICT. LOH was detected along the entire length of the chromosome arm and included the proximal region of 3p13-14.2 implicated in the hereditary form of renal cell carcinoma.^ If 3p LOH were a critical event in pancreatic islet cell tumorigenesis, then it should be expected that LOH in sporadic islet cell tumors would also be observed. We expanded LOH studies to include sporadic cases of PICT. Consistent LOH was observed on 3p with a highest frequency LOH in the region 3p21.2. This is the first evidence for an association between chromosome 3 loci and pancreatic islet cell tumorigenesis. (Abstract shortened by UMI.) ^

Variability in the Treatment of Elderly Patients with Stage IIIA (N2) Non–Small-Cell Lung Cancer

INTRODUCTION: We evaluated treatment patterns of elderly patients with stage IIIA (N2) non-small-cell lung cancer (NSCLC). METHODS: The use of surgery, chemotherapy, and radiation for patients with stage IIIA (T1-T3N2M0) NSCLC in the Surveillance, Epidemiology, and End Results-Medicare database from 2004 to 2007 was analyzed. Treatment variability was assessed using a multivariable logistic regression model that included treatment, patient, tumor, and census track variables. Overall survival was analyzed using the Kaplan-Meier approach and Cox proportional hazard models. RESULTS: The most common treatments for 2958 patients with stage IIIA (N2) NSCLC were radiation with chemotherapy (n = 1065, 36%), no treatment (n = 534, 18%), and radiation alone (n = 383, 13%). Surgery was performed in 709 patients (24%): 235 patients (8%) had surgery alone, 40 patients (1%) had surgery with radiation, 222 patients had surgery with chemotherapy (8%), and 212 patients (7%) had surgery, chemotherapy, and radiation. Younger age (p < 0.0001), lower T-status (p < 0.0001), female sex (p = 0.04), and living in a census track with a higher median income (p = 0.03) predicted surgery use. Older age (p < 0.0001) was the only factor that predicted that patients did not get any therapy. The 3-year overall survival was 21.8 ± 1.5% for all patients, 42.1 ± 3.8% for patients that had surgery, and 15.4 ± 1.5% for patients that did not have surgery. Increasing age, higher T-stage and Charlson Comorbidity Index, and not having surgery, radiation, or chemotherapy were all risk factors for worse survival (all p values < 0.001). CONCLUSIONS: Treatment of elderly patients with stage IIIA (N2) NSCLC is highly variable and varies not only with specific patient and tumor characteristics but also with regional income level.

Tumor budding in upper gastrointestinal carcinomas.

The basis of personalized medicine in oncology is the prediction of an individual's risk of relapse and death from disease. The presence of tumor budding (TB) at the tumor-host interface of gastrointestinal cancers has been recognized as a hallmark of unfavorable disease biology. TB is defined as the presence of dedifferentiated cells or small clusters of up to five cells at the tumor invasive front and can be observed in aggressive carcinomas of the esophagus, stomach, pancreas, ampulla, colon, and rectum. Presence of TB reproducibly correlates with advanced tumor stage, frequent lymphovascular invasion, nodal, and distant metastasis. The UICC has officially recognized TB as additional independent prognostic factor in cancers of the colon and rectum. Recent studies have also characterized TB as a promising prognostic indicator for clinical management of esophageal squamous cell carcinoma, adenocarcinoma of the gastro-esophageal junction, and gastric adenocarcinoma. However, several important issues have to be addressed for application in daily diagnostic practice: (1) validation of prognostic scoring systems for TB in large, multi-center studies, (2) consensus on the optimal assessment method, and (3) inter-observer reproducibility. This review provides a comprehensive analysis of TB in cancers of the upper gastrointestinal tract including critical appraisal of perspectives for further study.

Long-term outcome of patients with clinical stage I high-risk nonseminomatous germ-cell tumors 15 years after one adjuvant cycle of bleomycin, etoposide, and cisplatin chemotherapy

BACKGROUND To report the long-term results of adjuvant treatment with one cycle of modified bleomycin, etoposide, and cisplatin (BEP) in patients with clinical stage I (CS I) nonseminomatous germ-cell tumors (NSGCT) at high risk of relapse. PATIENTS AND METHODS In a single-arm, phase II clinical trial, 40 patients with CS I NSGCT with vascular invasion and/or >50% embryonal cell carcinoma in the orchiectomy specimen received one cycle of adjuvant BEP (20 mg/m(2) bleomycin as a continuous infusion over 24 h, 120 mg/m(2) etoposide and 40 mg/m(2) cisplatin each on days 1-3). Primary end point was the relapse rate. RESULTS Median follow-up was 186 months. One patient (2.5%) had a pulmonary relapse 13 months after one BEP and died after three additional cycles of BEP chemotherapy. Three patients (7.5%) presented with a contralateral metachronous testicular tumor, and three (7.5%) developed a secondary malignancy. Three patients (7.5%) reported intermittent tinnitus and one had grade 2 peripheral polyneuropathy (2.5%). CONCLUSIONS Adjuvant chemotherapy with one cycle of modified-BEP is a feasible and safe treatment of patients with CS I NSGCT at high risk of relapse. In these patients, it appears to be an alternative to two cycles of BEP and to have a lower relapse rate than retroperitoneal lymph node dissection. If confirmed by other centers, 1 cycle of adjuvant BEP chemotherapy should become a first-line treatment option for this group of patients.

Prognostic factors and outcomes in primary urethral cancer: results from the international collaboration on primary urethral carcinoma.

PURPOSE To evaluate risk factors for survival in a large international cohort of patients with primary urethral cancer (PUC). METHODS A series of 154 patients (109 men, 45 women) were diagnosed with PUC in ten referral centers between 1993 and 2012. Kaplan-Meier analysis with log-rank test was used to investigate various potential prognostic factors for recurrence-free (RFS) and overall survival (OS). Multivariate models were constructed to evaluate independent risk factors for recurrence and death. RESULTS Median age at definitive treatment was 66 years (IQR 58-76). Histology was urothelial carcinoma in 72 (47 %), squamous cell carcinoma in 46 (30 %), adenocarcinoma in 17 (11 %), and mixed and other histology in 11 (7 %) and nine (6 %), respectively. A high degree of concordance between clinical and pathologic nodal staging (cN+/cN0 vs. pN+/pN0; p < 0.001) was noted. For clinical nodal staging, the corresponding sensitivity, specificity, and overall accuracy for predicting pathologic nodal stage were 92.8, 92.3, and 92.4 %, respectively. In multivariable Cox-regression analysis for patients staged cM0 at initial diagnosis, RFS was significantly associated with clinical nodal stage (p < 0.001), tumor location (p < 0.001), and age (p = 0.001), whereas clinical nodal stage was the only independent predictor for OS (p = 0.026). CONCLUSIONS These data suggest that clinical nodal stage is a critical parameter for outcomes in PUC.

The in vitro impact of toothpaste extracts on cell viability.

Toothpastes contain three main components: detergents, abrasives, and fluoride. Detergents, particularly sodium lauryl sulfate, have been proposed as components that enable toothpastes to produce cytotoxic effects in vitro. However, not all toothpastes contain sodium lauryl sulfate, and almost no studies have found an association between detergents and the in vitro cytotoxicity of toothpastes. The present study examined the in vitro cytotoxicity of nine commercially available toothpastes containing four different detergents. Toothpastes were diluted in serum-free medium, centrifuged, and filter sterilized. The half-lethal concentration of the toothpaste-conditioned medium (TCM) was calculated based on the formation of formazan by gingival fibroblasts, oral squamous cell carcinoma HSC-2 cells, and L929 cells. Cell proliferation was analyzed, and live-dead staining was performed, after exposure of cells to conditioned medium prepared with 1% toothpaste (1% TCM). It was found that toothpastes containing sodium lauryl sulfate and amine fluoride strongly inhibited cell viability with the half-lethal concentration being obtained with conditioned medium prepared with approximately 1% toothpaste (1% TCM). Toothpastes containing cocamidopropyl betaine and Steareth-20 showed higher half-lethal concentration values, with the half-lethal concentration being obtained with conditioned medium prepared with 10% (10% TCM) and 70% (70% TCM) toothpaste, respectively. Proliferation and live-dead data were consistent with the cell-viability analyses. These results demonstrate that the type of detergent in toothpastes can be associated with changes in in vitro cell toxicity.

The transcriptional repressor Delta EF1 controls resistance to the EGFR inhibitor erlotinib in human HNSCC lines

Epidermal Growth Factor Receptor (EGFR) overexpression occurs in about 90% of Head and Neck Squamous Cell Carcinoma (HNSCC) cases. Aberrant EGFR signaling has been implicated in the malignant features of HNSCC. Thus, EGFR appears to be a logical therapeutic target with increased tumor specificity for the treatment of HNSCC. Erlotinib, a small molecule tyrosine kinase inhibitor, specifically inhibits aberrant EGFR signaling in HNSCC. Only a minority of HNSCC patients were able to derive a substantial clinical benefit from erlotinib. ^ This dissertation identifies Epithelial to Mesenchymal Transition (EMT) as the biological marker that distinguishes EGFR-dependent (erlotinib-sensitive) tumors from the EGFR-independent (erlotinib-resistant) tumors. This will allow us to prospectively identify the patients who are most likely to benefit from EGFR-directed therapy. More importantly, our data identifies the transcriptional repressor DeltaEF1 as the mesenchymal marker that controls EMT phenotype and resistance to erlotinib in human HNSCC lines. si-RNA mediated knockdown of DeltaEF1 in the erlotinib-resistant lines resulted in reversal of the mesenchymal phenotype to an epithelial phenotype and significant increase in sensitivity to erlotinib. ^ DeltaEF1 represses the expression of the epithelial markers by recruiting HDACs to chromatin. This observation allows us to translate our findings into clinical application. To test whether the transcriptional repression by DeltaEF1 underlines the mechanism responsible for erlotinib resistance, erlotinib-resistant lines were treated with an HDAC inhibitor (SAHA) followed by erlotinib. This resulted in a synergistic effect and substantial increase in sensitivity to erlotinib in the resistant cell lines. Thus, combining an HDAC inhibitor with erlotinib represents a novel promising pharmacologic strategy for reversing resistance to erlotinib in HNSCC patients. ^

Genetic epidemiology of childhood brain tumors

A rare familial cancer syndrome involving childhood brain tumors (CBT), breast cancer, sarcomas and an array of other tumors has been described (Li and Fraumeni 1969, 1975, 1982, 1987). A survey of CBT identified through the Connnecticut Tumor Registry in 1984 revealed a high frequency of CBT, leukemia and other childhood cancer in siblings of CBT patients (Farwell and Flannery, 1984). Other syndromes such as neurofibromatosis and nevoid basal cell carcinoma syndrome have also been associated with CBT; however, no systematic family studies have been conducted to determine the extent to which cancer aggregates in family members of CBT patients. This family study was designed to determine the frequency of cancer aggregation overall or at specific sites, to determine the frequency of known or potentially hereditary syndromes in families of CBT patients, and to determine a genetic model to characterize familial cancer syndromes and to identify specific kindreds to which such a model(s) might apply. This study includes 244 confirmed CBT patients referred to the University of Texas M. D. Anderson Cancer Center between the years 1944 and 1983, diagnosed under the age of 15 years and resident in the U.S. or Canada. Family histories were obtained on the proband's first (parents, siblings and offspring) and second degree (proband's aunts, uncles and grandparents) relatives following sequential sampling scheme rules. To determine if cancer aggregates in families, we compared the cancer experience in the population to that expected in the general population using Connecticut Tumor Registry calendar year, age, race and sex-specific rates. The standardized incidence ratio (SIR) for cancer overall was 0.91 (41 observed (O) and 44.94 expected (E); 95% Confidence Interval (CI) = 0.65-1.24). We observed a significant excess of colon cancer among the proband's first degree relatives (O/E = 5/1.64; 95% CI = 1.01-7.65), in particular those under age 45 year. Segregation analysis showed evidence for multifactorial inheritance in the small percentage (N = 5) of the families. ^

Study on the effect of metformin in patients of metastatic renal cell cancer with diabetes receiving tyrosine kinase inhibitor therapy

Objective: The primary objective of our study was to study the effect of metformin in patients of metastatic renal cell cancer (mRCC) and diabetes who are on treatment with frontline therapy of tyrosine kinase inhibitors. The effect of therapy was described in terms of overall survival and progression free survival. Comparisons were made between group of patients receiving metformin versus group of patients receiving insulin in diabetic patients of metastatic renal cancer on frontline therapy. Exploratory analyses were also done comparing non-diabetic patients of metastatic renal cell cancer receiving frontline therapy compared to diabetic patients of metastatic renal cell cancer receiving metformin therapy. ^ Methods: The study design is a retrospective case series to elaborate the response rate of frontline therapy in combination with metformin for mRCC patients with type 2 diabetes mellitus. The cohort was selected from a database, which was generated for assessing the effect of tyrosine kinase inhibitor therapy associated hypertension in metastatic renal cell cancer at MD Anderson Cancer Center. Patients who had been started on frontline therapy for metastatic renal cell carcinoma from all ethnic and racial backgrounds were selected for the study. The exclusion criteria would be of patients who took frontline therapy for less than 3 months or were lost to follow-up. Our exposure variable was treatment with metformin, which comprised of patients who took metformin for the treatment of type 2 diabetes at any time of diagnosis of metastatic renal cell carcinoma. The outcomes assessed were last available follow-up or date of death for the overall survival and date of progression of disease from their radiological reports for time to progression. The response rates were compared by covariates that are known to be strongly associated with renal cell cancer. ^ Results: For our primary analyses between the insulin and metformin group, there were 82 patients, out of which 50 took insulin therapy and 32 took metformin therapy for type 2 diabetes. For our exploratory analysis, we compared 32 diabetic patients on metformin to 146 non-diabetic patients, not on metformin. Baseline characteristics were compared among the population. The time from the start of treatment until the date of progression of renal cell cancer and date of death or last follow-up were estimated for survival analysis. ^ In our primary analyses, there was a significant difference in the time to progression of patients receiving metformin therapy vs insulin therapy, which was also seen in our exploratory analyses. The median time to progression in primary analyses was 1259 days (95% CI: 659-1832 days) in patients on metformin therapy compared to 540 days (95% CI: 350-894) in patients who were receiving insulin therapy (p=0.024). The median time to progression in exploratory analyses was 1259 days (95% CI: 659-1832 days) in patients on metformin therapy compared to 279 days (95% CI: 202-372 days) in non-diabetic group (p-value <0.0001). ^ The median overall survival was 1004 days in metformin group (95% CI: 761-1212 days) compared to 816 days (95%CI: 558-1405 days) in insulin group (p-value<0.91). For the exploratory analyses, the median overall survival was 1004 days in metformin group (95% CI: 761-1212 days) compared to 766 days (95%CI: 649-965 days) in the non-diabetic group (p-value<0.78). Metformin was observed to increase the progression free survival in both the primary and exploratory analyses (HR=0.52 in metformin Vs insulin group and HR=0.36 in metformin Vs non-diabetic group, respectively). ^ Conclusion: In laboratory studies and a few clinical studies metformin has been proven to have dual benefits in patients suffering from cancer and type 2-diabetes via its action on the mammalian target of Rapamycin pathway and effect in decreasing blood sugar by increasing the sensitivity of the insulin receptors to insulin. Several studies in breast cancer patients have documented a beneficial effect (quantified by pathological remission of cancer) of metformin use in patients taking treatment for breast cancer therapy. Combination of metformin therapy in patients taking frontline therapy for renal cell cancer may provide a significant benefit in prolonging the overall survival in patients with metastatic renal cell cancer and diabetes. ^

Examination of synthetic retinoid -induced apoptosis in cutaneous squamous cell carcinomas: Mechanisms and implications for chemoprevention and chemotherapy with retinoids

Non-melanoma skin cancers, including basal cell carcinoma and squamous cell carcinoma (SCC), are the most common neoplasms in the United States with a lifetime risk nearly equal to all other types of cancer combined. Retinoids are naturally occurring and synthetic analogues of vitamin A that bind to nuclear retinoid receptors and modulate gene expression as a means of regulating cell proliferation and differentiation. Retinoids have been employed for many years in the treatment of various cutaneous lesions and for cancer chemoprevention and therapy. The primary drawback limiting the use of retinoids is their toxicity, which is also associated with receptor-gene interactions. In this study, the effects of the synthetic retinoids N-(4-hydroxyphenyl)retinamide (4HPR) and 6-[3-(1-adamantyl)-4-hydroxyphenyl]-2-naphthalene carboxylic acid (CD437) were examined in cutaneous keratinocytes. Four human cutaneous SCC cell lines were examined along with normal human epidermal keratinocyte (NHEK) cells from two donors. Sensitivity to 4HPR or CD437 alone or in combination with other agents was determined via growth inhibition, cell cycle distributions, or apoptosis induction. Both synthetic retinoids were able to promote apoptosis in SCC cells more effectively than the natural retinoid all-trans retinoic acid. Apoptosis could not be inhibited by nuclear retinoic acid receptor antagonists. In NHEK cells, 4HPR induced apoptosis while CD437 promoted G1 arrest. 4HPR acted as a prooxidant by generating reactive oxygen species (ROS) in SCC and NHEK cells. 4HPR-induced apoptosis in SCC cells could be inhibited or potentiated by manipulating cellular defenses against oxidative stress, indicating an essential role for ROS in 4HPR-induced apoptosis. CD437 promoted apoptosis in SCC cells in S and G2/M phases of the cell cycle within two hours of treatment, and this rapid induction could not be blocked with cycloheximide. This study shows: (1) 4HPR- and CD437-induced apoptosis do not directly involve a traditional retinoid pathway; (2) 4HPR can act as a prooxidant as a means of promoting apoptosis; (3) CD437 induces apoptosis in SCC cells independent of protein synthesis and is potentially less toxic to NHEK cells; and (4) 4HPR and CD437 operate under different mechanisms with respect to apoptosis induction and this may potentially enhance their therapeutic index in vivo. ^

Effects of exogeneous p53 on growth suppression, apoptosis, and differentiation in oral cancer cell lines

The p53 gene is known to be one of the most commonly mutated genes in human cancers. Many squamous cell carcinomas of the head and neck (SCCHNs) have been shown to contain nonfunctional p53 as well. The use of p53-mediated gene therapy to treat such cancers has become an intensive area of research. Although there have been varied treatment responses to p53 gene therapy, the role that endogenous p53 status plays in this response has not been thoroughly examined. Because of this, the hypothesis of this study examined the role that the endogenous p53 status of cells plays in their response to p53 gene therapy. To test this, an adenoviral vector containing p53 (p53FAd) was administered to three squamous cell carcinoma lines with varied endogenous p53. The SCC9 cell line demonstrates no p53 protein expression, the SCC4 cell line displays overexpression of a mutant p53 protein, and the 1986LN cell line displays low to no expression of wild-type p53 protein as a consequence of human papillomavirus infection. After treatment with p53FAd, the cells were examined for evidence of exogenous p53 expression, growth suppression, alterations in cellular proteins, G1 growth arrest, apoptosis, and differentiation state. Each cell line exhibited exogenous p53 protein. Growth suppression was seen most prominently in the SCC9 cells, to some extent in the 1986LN cells, and little was seen with the SCC4 cells. WAF1/p21 protein was induced in all three cell lines, while PCNA, bcl-2, and bax expression was not significantly affected in any of the lines. Apoptosis developed first in SCC9 cells, next in 1986LN cells, with little seen in the SCC4 cells. The SCC9 line was the only line to show significant GI growth arrest. No significant differences were observed in the overall expression of differentiation markers, aside from increased keratin 13 mRNA levels in all three lines indicating a possible tendency toward differentiation. This study indicates that the endogenous p53 status of squamous cell carcinomas appears to play a critical role in determining the response to p53 adenoviral gene therapy. ^

Virus del papiloma humano : presentación oral y su relación con el carcinoma espinocelular

El virus del papiloma humano (VPH) (HPV en su sigla en inglés) es un virus ADN con especial afinidad por células epiteliales, tanto cutáneas como mucosas, que incluyen el epitelio del cérvix, región anogenital y orofaríngea. Existen más de 120 subtipos de VPH subdivididos en dos grupos según su bajo o alto riesgo de inducir actividad oncogénica. En cavidad oral la manifestación clínica benigna de la infección es el papiloma plano.Sin embargo, un 12% de los carcinoma~ o rofaríngeos son causados por este virus. Se ha demostrado que la infección por VPH tiene un papel independiente como factor de riesgo para el desarrollo de carcinoma espinocelular en cavidad oral.

Non-p53 p53RE binding protein, a human transcription factor functionally analogous to P53

The transactivation activity of the p53 tumor suppressor protein is critical for regulating cell growth and apoptosis. We describe the identification of a transcription factor that is functionally similar to p53 and contains the same DNA binding and transcription activities specific for the p53 responsive DNA element (p53RE). This protein was highly purified through chromatography from HeLa cell extracts. The purified protein was able to bind specifically to the p53RE derived from a p21waf1 promoter and to stimulate p53RE-dependent transcription but not basal transcription in vitro. Its DNA-binding activity was inhibited by the wild type but not mutant p53RE-containing DNA oligomers. Also, this p53RE-binding activity was found in human p53 null Saos-2 osteosarcoma and H1299 small cell lung carcinoma cells. Interestingly, this activity exhibited a p53RE sequence preference that was distinct from the p53 protein. The activity is neither p53 nor p73, because anti-p53 or anti-73 antibodies were unable to detect this purified protein nor were the antibodies able to alter the p53-like activity, the p53RE-protein complex. These results demonstrate that, besides p73, an additional p53-like protein exists in cells, which is named NBP for non-p53, p53RE binding protein.

Human carbonic anhydrase XII: cDNA cloning, expression, and chromosomal localization of a carbonic anhydrase gene that is overexpressed in some renal cell cancers

We report the cloning and characterization of a tumor-associated carbonic anhydrase (CA) that was identified in a human renal cell carcinoma (RCC) by serological expression screening with autologous antibodies. The cDNA sequence predicts a 354-amino acid polypeptide with a molecular mass of 39,448 Da that has features of a type I membrane protein. The predicted sequence includes a 29-amino acid signal sequence, a 261-amino acid CA domain, an additional short extracellular segment, a 26-amino acid hydrophobic transmembrane domain, and a hydrophilic C-terminal cytoplasmic tail of 29 amino acids that contains two potential phosphorylation sites. The extracellular CA domain shows 30–42% homology with known human CAs, contains all three Zn-binding histidine residues found in active CAs, and contains two potential sites for asparagine glycosylation. When expressed in COS cells, the cDNA produced a 43- to 44-kDa protein in membranes that had around one-sixth the CA activity of membranes from COS cells transfected with the same vector expressing bovine CA IV. We have designated this human protein CA XII. Northern blot analysis of normal tissues demonstrated a 4.5-kb transcript only in kidney and intestine. However, in 10% of patients with RCC, the CA XII transcript was expressed at much higher levels in the RCC than in surrounding normal kidney tissue. The CA XII gene was mapped by using fluorescence in situ hybridization to 15q22. CA XII is the second catalytically active membrane CA reported to be overexpressed in certain cancers. Its relationship to oncogenesis and its potential as a clinically useful tumor marker clearly merit further investigation.