Chromosome 7 aneuploidy in clear cell and papillary renal cell carcinoma: Detection using silver in situ hybridization technique

Background: Chromosome 7 aberrations in renal cell carcinoma (RCC) have been reported in papillary renal cell carcinoma (pRCC) and clear cell renal cell carcinoma (ccRCC). However, the implication of these anomalies on prognosis and survival is still unclear. RCC Chromosome 7 aberrations have commonly been detected by fluorescent in situ hybridization and chromogenic in situ hybridization but not silver in situ hybridization (SISH). Aim: The purpose was to report chromosome 7 aberrations in ccRCC and pRCC using SISH in paraffin-embedded tissues and determine the association between the anomalies with clinical and pathological features. Materials and Methods: Cases of ccRCC and pRCC from University Malaya Medical Centre (2001-2009) were analyzed. Chromosome 7 staining was performed using an automated SISH method and association tests between chromosomal anomalies, clinical features and survival were performed. Results: SISH is a feasible technique to detect chromosome 7 aberration in RCC. Chromosome 7 aberrations with nuclear grading, staging and survival yielded no significant correlation. Surprisingly, there was a significant association between gender and chromosome 7 expressions. Though grade did not reach statistical significance for survival in our RCC cases, there was a significant correlation between overall survival with race and stage. Conclusion: Chromosome 7 aberrations in ccRCC showed no prognostic significance. Nevertheless, staging and grading systems that include prognostic variables could hold better promise.