[The annual meeting of the American Association for Cancer Research (AACR), Toronto (Ontario), 18-22 May 1995].

The state of the art concerning major biological phenomenons of importance for current research on urological cancers is first briefly presented, followed by notes on the more outstanding presentations in this field. These notes are organized in a synthetic fashion, in order to point to the meaning of the hypotheses and findings presented, when taken together, as they pertain to the understanding of the mechanisms at play in urological cancers, as we see them in 1995. Some concepts seem to have now reached a point where we can expect to see some applications in a not so distant future: in prostate cancer, it is confirmed that the machinery of apoptosis is functional even in the hormone-insensitive cells, suggesting that its enhancement might be useful in these often difficult situations; techniques to detect circulating malignant cells, which have been greatly refined (RT-PCR of PSA and PSM), are now extremely sensitive and may prove unvaluable in providing intermediate end points to compare the relative efficacy of treatment regimens in clinical trials; the symposium on prostate cancer screening by PSA dosage was an excellent opportunity to review extensively the data available on this topic, but -as expected- it could not decide on some essential issues; in bladder tumors, data on the expression of adhesion molecules (CD44 variant) are still preliminary, but some provocative observations have been reported (presence on mature ARN, only in bladder cancer cells, of intronic sequences that have not been excised); in renal cell cancer, a considerable amount of knowledge has accumulated on the von Hippel-Lindau gene, a putative anti-oncogene, and work is in progress to define the function of its protein; finally, pathways essential to understanding and treating cancer have been dissected, particularly the apoptosis-proliferation network, and the involvement in it of p53, Waf-1 and the bcl-2 gene family cascade.