PROTEIN ABUNDANCY AND MESSENGER-RNA LEVELS OF THE ADIPOCYTE-TYPE FATTY-ACID-BINDING PROTEIN CORRELATE IN NONINVASIVE AND INVASIVE BLADDER TRANSITIONAL-CELL CARCINOMAS

The adipocyte type fatty acid-binding protein (A-FABP) is a small mole cular weight fatty acid-binding protein whose expression correlates bo th with the grade of atypia and the stage of bladder transitional cell carcinomas (TCCs). To determine if the protein abundancy correlates w ith the mRNA levels in non-invasive and invasive lesions, we have anal ysed fresh TCCs (grade II, Ta; grade III, T2-4) by two-dimensional pol yacrylamide gel electrophoresis (2D-PAGE) and measured the mRNA levels using the reverse transcription linked polymerase chain reaction (RT- PCR). Overall, the results showed a good correlation between protein a bundancy and mRNA levels, indicating that the lack of expression of th e protein observed in some lesions reflects low levels of transcriptio n of the A-FABP gene rather than translational regulation. In addition , our studies showed that the loss of A-FABP protein observed in some tumors is not compensated by an increase in the skin fatty acid-bindin g protein PA-FABP, as is the case in the A-FABP knockout mice.