Mucinous Tubular and Spindle Cell Carcinoma of the Kidney Is Genomically Distinct from Papillary Renal Cell Carcinoma
Cheng C Huang, Cristina Magi-Galluzzi, Karen Smith, Ming Zhou. New York University Langone Medical Center, New York, NY; Cleveland Clinic, Cleveland, OH
Background: Mucinous tubular and spindle cell carcinoma of the kidney (MTSCCA) is an uncommon renal cell carcinoma (RCC) subtype included in 2004 WHO classification. MTSCCS has morphological and immunohistochemical resemblance to papillary renal cell carcinoma (PRCC), which has created confusion over the relationship between the two. The genetic characteristics of MTSCCA have been studied in only small number of cases and are not well established.
Design: 10 type1 PRCC, 13 type 2 PRCC and 8 MTSCCA were subject to array-based comparative genomic hybridization. Genomic DNA was extracted from formalin-fixed, paraffin-embedded tumor and adjacent normal tissue and hybridized to Affymetrix SNP 6.0 Array chips, which contained 1.8 million genetic markers, including 906,600 single nucleotide polymorphisms (SNPs) and 946,000 probes for copy number variation (CNV) detection.
Results: Type 1 and 2 PRCCs had genomic alterations (amplifications [+] and deletions [-]) of similar patterns involving multiple genomic sites, although the frequency of the alterations was in general higher in type 1 PRCC. These alterations included those previously reported in PRCCs, including +3q, +7, +16, +17, and –Y, and all these changes were found in >50% cases. Other previously documented changes were not found in this study, including +8, +12, +20, -1p, and -9p21. -3p21 was a novel alteration not previously reported and detected in 60% (6/10) of type 1 PRCC. MTSCCA demonstrated multiple genomic alterations that were previously reported, including -1, -4, -6, -9, -13, -14 and +11, and these changes were found in >50% MTSCCA. Comparing PRCC and MTSCCA, there was no overlap in the patterns of genomic alteration between the two types of tumors. Specifically, +7, +17 and –Y were not observed in MTSCCA.
Conclusions: This study provides further evidence that MTSCCA and PRCC are genomically distinct tumors. Mining the genomic data of these tumors may yield important information regarding their pathogenesis, diagnosis and therapeutics.
Category: Genitourinary (including renal tumors)
Monday, March 4, 2013 8:00 AM
Proffered Papers: Section A, Monday Morning