ABSTRACT Purpose to determine the usefulness of serum TF as a potential marker for patients with clear cell RCC. Materials and Methods prospective study of 30 patients with clear cell RCC submitted to nephrectomy and 16 controls without clear cell RCC treated surgically for other conditions. TF is a endothelium marker that was correlated with worse prognosis in a variety of solid tumors including RCC. Serum TF was collected before surgery at the operating room and in the postoperative setting after at least four weeks. Serum samples were analyzed with a commercial ELISA kit for human TF (R&D Systems®). Results Mean preoperative serum TF levels in clear cell RCC patients and in controls were 66.8 pg/dL and 28.4 pg/dL, respectively (p<0.001). Mean postoperative serum TF levels in clear cell RCC patients were 26.3 pg/dL. In all patients with clear cell RCC postoperative serum levels of TF were lower, with a mean reduction of 41.6 pg/dL in the postoperative setting (p<0.001). Linear regression revealed that tumor size was correlated with the postoperative reduction of serum TF levels (p=0.037). Conclusions We have shown a 3-fold reduction in the median preoperative serum levels of TF in patients with clear cell RCC after surgery. We have also shown a difference of the same magnitude in the serum levels of TF compared with those of a control group of patients with benign diseases. TF appears to be a useful serum marker for the presence of clear cell RCC. Further studies are needed to validate these findings.

Body color polymorphism of urban populations of cosmopolite fly Drosophila kikkawai Burla, 1954 was investigated in relation to its possible association with environmental temperature. Samples of D. kikkawai were collected in spring, summer, autumn and winter between 1987 to 1988, in zones with different levels of urbanization in the southern Brazilian city of Porto Alegre, Rio Grande do Sul. A clear association was observed between darker flies and both seasons with low temperatures and areas of low urbanization (where temperature is generally lower than in urbanized areas). Results of preliminary laboratory experiments involving six generations of flies grown in chambers at temperatures of 17º and 25ºC confirmed this tendency to a relationship between body color and temperature, with allele frequency of the main gene involved in body pigmentation changing over time.