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.) ^

Identification of a novel tumor suppressor gene on human chromosome 3p14-p12 involved in renal cell carcinoma

Nonpapillary renal cell carcinoma (RCC) is an adult cancer of the kidney which occurs both in familial and sporadic forms. The familial form of RCC is associated with translocations involving chromosome 3 with a breakpoint at 3p14-p13. Studies focused on sporadic RCC have shown two commonly deleted regions at 3p14.3-p13 and 3p21.3. In addition, a more distal region mapping to 3p26-p25 has been linked to the Von Hippel Lindau (VHL) disease gene. A large proportion of VHL patients develop RCC. The short arm of human chromosome 3 can, therefore, be dissected into three distinct regions which could encode tumor suppressor genes for RCC. Loss or inactivation of one or more of these loci may be an important step in the genesis of RCC.^ I have used the technique of microcell-mediated chromosome transfer to introduce an intact, normal human chromosome 3 and defined fragments of 3p, dominantly marked with pSV2neo, into the highly malignant RCC cell line SN12C.19. The introduction of chromosome 3 and of a centric fragment of 3p, encompassing 3p14-q11, into SN12C.19 resulted in dramatic suppression of tumor growth in nude mice. Another defined deletion hybrid contained the region 3p12-q24 of the introduced human chromosome and failed to suppress tumorigenicity. These data define the region 3p14-p12, the most proximal region of high frequency allele loss in sporadic RCC as well as the region containing the translocation breakpoint in familial RCC, to contain a novel tumor suppressor locus involved in RCC. We have designated this locus nonpapillary renal cell carcinoma-1 (NRC-1). Furthermore, we have functional evidence that NRC-1 controls the growth of RCC cells by inducing rapid cell death in vivo. ^