7q31 (C-MET) Amplification Is a Constant Finding in Tubulo-Cystic Renal Cell Carcinoma.
Matteo Brunelli, Diego Segala, Stefano Gobbo, Samantha Bersani, Emma Bragantini, Marina Gardiman, Isabel Alvarado Cabrero, Marco Chilosi, Guido Martignoni. University of Verona, Italy; S. Chiara Hospital, Trento, Italy; Univeristy of Padua, Italy; Centro Medico, Mexico City, Mexico
Background: Among new emerging described renal neoplasms, the tubulo-cystic renal cell carcinoma may be considered a unique morphologic entity with distinctive gross and microscopic features. However, before it is accepted as a distinct renal cell carcinoma subtype, further studies are needed to document a characteristic molecular pattern associated with this tumor. It has also been questioned its relationship to papillary renal cell carcinoma. We sought to evaluate the fluorescent molecular signature expanding the chromosomal in situ analysis.
Design: Nine tubulo-cystic renal cell carcinomas were recruited, 5 of which from a single patient. Clinico-pathological analyses were recorded. Immunophenotypical analysis using monoclonal antibody against cytokeratin 7 (CK7), S100A1, parvalbumin (PV), racemase, CD10 were performed. Centromeric probes for chromosomes 7, 12, 16, 17, 20 and Y and locus specific probes (LSI) for 7q31 (c-met), 7p12 (EGFR), 17p13.1 (p53), 17q11.2-12 (Her-2), 17q21-q22 (Topoisomerase-IIa) were tested.
Results: Patients age ranged from 45 to 67, with a male preponderance (5:1). A patient presented a synchronous papillary renal cell carcinoma. Tumours had a diameter ranged from 0,8 to 3,5 cm and all staged pT1a. Furhman grade was G3 in all neoplasms. Cases stained for CD10 (10/10, 100%), S100A1 (10/10, 100%) and racemase (9/10, 90%); PV was weakly and focally positive in 3 tumors (3/10, 30%), whereas only one case immunoexpressed CK7 (1/10, 10%). LSI-7q31 (C-MET) was gained in all five cases, but only two showed gains of centromeric signals for chromosome 7, and LSI-7p12 (EGFR) resulted disomic. Regarding chromosome 17 two out of five cases showed gains of centromeric signals, whereas three cases showed gains of LSI-17p13.1 (p53), LSI-17q11.2-12 (Her-2) and LSI-17q21-q22 (topoisomerase-IIa). Only one case showed loss of Y and not alteration were identified for chromosomes 12, 16 and 20.
Conclusions: In conclusion: 1) tubulo-cystic renal cell carcinomas constantly show 7q31 (C-MET) amplification; 2) this is the single chromosome abnormality in common with those described in papillary renal cell carcinoma.
Category: Genitourinary (including renal tumors)
Wednesday, March 2, 2011 9:30 AM
Poster Session V # 95, Wednesday Morning