Effect of menstrual cycle on protein expression in human uterine leiomyomas

Tissue proteins in paired samples of uterine leiomyomas and normal myometria from 26 patients were compared after extraction with 9 M urea, separation by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE), and visualization by silver staining. A creatine kinase carbamylation train and a rat heart extract were used as internal standards for the relative charge and the relative molecular weight (Mr) scales, respectively. Two groups of four proteins each, a first group of Mr = 34,500 (34K) and relative charge of creatine kinase of -14 to -21(P34a-d) and a second group of Mr = 56,000 (56K) and relative charge of creatine kinase less than -23(P56a-d), were more frequently expressed in uterine leiomyoma tissue than in normal myometrial tissue: P34, 14 of 26 (53.8%) in tumors and zero of 26 (0%) in normal myometria; P56a&d, 17 of 26 (65.3%); P56b&c, 20 of 26 (76.9%) in tumors and P56a&d, zero of 26 (0%); and P56b&c, 12 of 26 (46.1%) in normal myometria. Both P34 and P56 were expressed more frequently in the uterine leiomyoma during the proliferative phase than during the nonproliferative phase (P34 in proliferative phase: 12 of 13, 92.3%; and in nonproliferative phase: two of 13, 15.3%; P56a-d in proliferative phase: 13 of 13, 100%; and in nonproliferative phase: P56a&d, four of 13, 30.7%, and P56b&c, seven of 13, 53.8%). The cyclic expression of P34 and P56 suggests that their synthesis is related to the intrinsic hormonal environment of the tumors.