[986] Cytogenomic Molecular Profiles of Tubulocystic Carcinoma of the Kidney

Gabriela Quiroga-Garza, Alberto G Ayala, Luan Truong, Mahul B Amin, Komal Arora, Isabel Alvarado-Cabrero, Karime Cuevas-Ocampo, Federico A Monzon. The Methodist Hospital Weill Medical College, Cornell University, Houston, TX; Cedars-Sinai Medical Center, Los Angeles, CA; Mexican Oncology Hospital, IMSS, Mexico City, DF, Mexico

Background: Tubulocystic renal cell carcinoma is not yet included in the latest WHO classification of renal neoplasms. Considered a variant of collecting duct carcinoma, now is regarded as an independent pathologic entity. Studies have reported chromosomal imbalances in this tumor similar to those seen in papillary RCC, but a genome-wide chromosome copy number analysis has not been performed previously.
Design: Eight cases of tubulocystic carcinoma were identified from institutional archives under IRB approved protocols. H&E-stained slides were reviewed, confirming the diagnosis and outline of the tumor and nontumorous components, which were microdissected from 10um unstained sections. After total DNA extraction from each specimen, DNA copy number variation and loss of heterozygosity were analyzed using Affimetrix 250K Nsp genotyping arrays.
Results: Clinicopathological information was available for six cases (6/8). Five male and one female patients, ages 39 to 70 years (mean: 54.5); tumor size was 2.5 to 6.5 (mean: 3.8). In two patients, there were associated synchronous tumors (papillary RCC and clear cell RCC). All tumors showed chromosomal abnomalities, with the number of affected chromosomes ranging from 1 to 12. Loss of chromosome 9 and gain of chromosome 17 were observed in all cases except one (88%). Gain of chromosome 16 was seen in 5 of 8 cases (62%) and gain of 8 was seen in 4 of 8 cases (50%). Uniparental disomy was present in two of the examined cases.
Conclusions: Tubulocystic carcinoma of the kidney not only shows distinct clinicopathological features, but appears to be characterized by recurrent loss of chromosome 9 and gain of 17. This differs from the profile of other renal cell tumors, particularly collecting duct carcinomas, supporting the concept that tubulocystic carcinoma is a different tumor entity. Cytogenetic studies in collecting duct carcinoma have not shown consistent chromosomal abnormalities. Although gain of chromosome 17 is also observed in papillary renal cell carcinoma, only one of the 8 tubulocystic carcinoma showed gain of 7, suggesting that these two tumors are not related at the genetic level. Our results suggest that the recurrent chromosomal imbalances seen in tubulocystic carcinoma can be used in the differential diagnosis from other cystic renal neoplasms.
Category: Genitourinary (including renal tumors)

Wednesday, March 21, 2012 9:30 AM

Poster Session V # 84, Wednesday Morning

 

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