Molecular study of a new family with hereditary renal cell carcinoma and a translocation t(3;8)(p13;q24.1)

Abstract.

An alternative model has been proposed for the development of clear-cell renal cell carcinoma (RCC) in families where chromosome 3 translocations segregate with the disease. In this model, the existence of a translocation involving chromosome 3 would favour the non-disjunctional loss of the derivative chromosome carrying the 3p segment. Additionally, subsequent somatic mutations in the VLH gene, located in 3p25–26, would inactivate this tumour suppressor gene. In the present work, we describe a new family with two clear-cell RCC affected members and a t(3;8)(p13;q24.1) translocation in two consecutive generations. We observed loss of the derivative chromosome carrying the 3p segment (der(8)) and somatic mutation of the VHL gene in the left-kidney tumoral tissue of the proband. His right-kidney tumour carried a different VHL mutation and loss of heterozygosity (LOH) was not detected. The mother of the proband was also clear-cell RCC-affected but the tumoral tissue analysed did not carry any VHL gene mutations. Another member of the family, a maternal aunt, had a papillary RCC and did not carry this translocation, the LOH on 3p or the VHL somatic mutations. Haplotype analysis of the three affected members revealed that they did not inherit a common region on 3p, confirming the different genetic origin of both tumour types. Finally, the presence of RCC in other non-available members of the family highlights the overall risk for RCC in families with chromosome 3 translocations. In the present work, we have confirmed the proposed mechanism for the development of clear-cell RCC in this family, although we cannot discard the existence of other genes, in addition to VHL, being involved in hereditary RCC.