DNA-PLOIDY PATTERN IN PAPILLARY RENAL-CELL CARCINOMA - CORRELATION WITH CLINICOPATHOLOGICAL PARAMETERS AND SURVIVAL

Papillary renal cell carcinoma (PRCC) is a less frequent histomorpholo gic variant of renal cortical carcinoma (RCC). Morphologically, PRCC d iffers from other forms of RCC in that it is associated with frequent tumor infiltration by macrophages and lymphocytes, and a tendency for central necrosis and cystic change. Follow-up data revealed that survi val rates are higher among patients with PRCC than among patients with other forms of RCC. The authors explore the DNA content in a series o f PRCC and correlate the findings with nuclear grade, pathological sta ge and survival. Using Flow Cytometry, we analysed the DNA ploidy patt ern of 37 paraffin-embedded PRCC. At least 3 tumor fragments were anal ysed in each case. To obtain the reference diploid standard, the non-t umor renal tissue from the same case was added to the solution. Tumor ploidy was classified as diploid and aneuploid. The degree of DNA cont ent abnormalities was given by the DNA Index (DI). An aneuploid DNA pr ofile was found in 65% of the tumors. 25% of the aneuploid tumors pres ented near diploid peaks (1.10 < DI < 1.30; low degree aneuploidy), 25 % were hyperdiploid, while 22% had a hypodiploid profile (DI < 0.90). A homogeneous DNA ploidy pattern was observed in 25 tumors (68%), whil e there was intratumoral heterogeneity in 12 tumors (32%). Patients wi th aneuploid DNA patterns had high grade/stage tumors and died at the end of the follow-up period, while patients with diploid/near diploid profiles had low grade/stage tumors and survived. However, the multi-w ay analysis of variance performed in order to investigate the prognost ic significance of ploidy pattern against tumor stage and grade showed a highly significant main effect of ploidy pattern, Moreover, the pat ients with hypodiploid DNA profile presented the worst prognosis. Thes e results suggest that the DNA profile of PRCC is a highly significant prognostic index.