Renal cell carcinoma and a constitutional t(11;22)(q23;q11.2): case report and review of the potential link between the constitutional t(11;22) and cancer

The Pathologic and Molecular Genetic Landscape of the Hereditary Renal Cancer Predisposition Syndromes

It is estimated that 5-8% of renal tumors are hereditary in nature with many inherited as autosomal dominant. These tumors carry a unique spectrum of pathologic and molecular alterations, the knowledge of which is expanding in the recent years. Indebted to this knowledge, many advances in treatment of these tumors have been achieved. In this review, we summarize the current understanding of the genetic renal neoplasia syndromes, the clinical and pathologic presentations, their molecular pathogenesis, the advances in therapeutic implications and targeted therapy.

Characterization of renal cell carcinoma-associated constitutional chromosome abnormalities by genome sequencing

Constitutional translocations, typically involving chromosome 3, have been recognized as a rare cause of inherited predisposition to renal cell carcinoma (RCC) for four decades. However, knowledge of the molecular basis of this association is limited. We have characterized the breakpoints by genome sequencing (GS) of constitutional chromosome abnormalities in five individuals who presented with RCC. In one individual with constitutional t(10;17)(q11.21;p11.2), the translocation breakpoint disrupted two genes: the known renal tumor suppressor gene (TSG) FLCN (and clinical features of Birt‐Hogg‐Dubé syndrome were detected) and RASGEF1A. In four cases, the rearrangement breakpoints did not disrupt known inherited RCC genes. In the second case without chromosome 3 involvement, the translocation breakpoint in an individual with a constitutional t(2;17)(q21.1;q11.2) mapped 12 Kb upstream of NLK. Interestingly, NLK has been reported to interact indirectly with FBXW7 and a previously reported RCC‐associated translocation breakpoint disrupted FBXW7. In two cases of constitutional chromosome 3 translocations, no candidate TSGs were identified in the vicinity of the breakpoints. However, in an individual with a constitutional chromosome 3 inversion, the 3p breakpoint disrupted the FHIT TSG (which has been reported previously to be disrupted in two apparently unrelated families with an RCC‐associated t(3;8)(p14.2;q24.1). These findings (a) expand the range of constitutional chromosome rearrangements that may be associated with predisposition to RCC, (b) confirm that chromosome rearrangements not involving chromosome 3 can predispose to RCC, (c) suggest that a variety of molecular mechanisms are involved the pathogenesis of translocation‐associated RCC, and (d) demonstrate the utility of GS for investigating such cases.

Foci of Entotic Nuclei in Different Grades of Noninherited Renal Cell Cancers

We report here an intriguing pattern in nuclear appearance of renal clear cell cancer. In low grade clear cell cancer, detailed examination showed that in many cells, two or more nuclei were within the confines of a single cell membrane. This likely resulted from a cell being contained within its neighboring cell. Consequently, this resulted in appearance of multicellularity. This appearance of the nuclei were not associated with mitotic figures, suggesting that these did not result from nuclear fission. Additionally, the cells containing this nuclei did not show any evidence of cytokinesis including equatorial tapering, suggesting that the process may have resulted from cytokinesis failure. In some sections of higher grade clear cell cancer, these appearance were higher, though we did not observe any frank syncytium formation. On careful observation, there were isolated events of fusion of nuclei within a single cell in different grades of renal cell cancers. There occurrence was more frequent in higher grades of clear cell renal cancer and metastatic clear cell carcinoma. These features were also demonstrable in multiple fields of lower grades of clear cell carcinoma. This phenomenon of entosis may contribute to aneuploidy and tumor progression to dysplastic stages and genomic instability in renal cancers. Future studies are aimed at delineating the cell-cell boundaries and the mechanism contributing to this observation, either from peripheral cell engulfing or failure of cytosolic division for cell separation.