Telomeric associations in two cases of papillary renal cell carcinoma. J. Tsai, B. Huang, M. Thangavelu, N. Qin, M. LeMieu, S. Lass. cytogenetics, Genzyme genetics, Corona, CA.
   Telomere plays an important role in maintaining chromosome integrity and stability. Telomere association(TAS) is a rare phenomenon and has been reported in varioun solid tumors include renal cell carcinoma. TAS was proposed as one of the mechanisms of oncogenesis in these tumors. We present two cases of telomeric associations in papillary renal cell carcinoma. Multiple clonal numerical and structural rearrangements were observed in both cases, including gain and loss of chromosomes 7, 12, 17, and Y, frequent findings in papillary renal cell carcinoma. In addition, numerous TASs were observed. In the first case, TASs involved chromosomes 2, 4, 8, 12, 14, 15, 16, 17, 21, 22, and X were observed. In the second case, TASs were even more extensive, and involved chromosomes 1, 3, 7, 8, 9, 10, 16, 17, 19, 20, and 21. The majority of the associations were clonal and included chromosomes 16, 17, 19, and 20. A double telomeric association involves chromosomes 16, 19, and 21 was also observed. Overeall, twenty two different telomeric associations were observed in this case. The presence of multiple TASs, in addition to other chromosome abnormalities suggests chromosome instability and may be a sign of tumor progression.