Expression of the steroid receptor RNA activator in human breast tumors

The expression of the recently described steroid receptor RNA activator (SR A) was measured by semiquantitative reverse transcription-PCR within 27 ind ependent breast tumors, spanning a wide spectrum of grade and estrogen rece ptor (ER) and progesterone receptor (PR) levels. Subgroup analysis showed t hat SRA expression was similar in ER+/PR+ (median = 65.5, n = 8) and in ER- /PR- (median = 94.6, n = 5) tumors. Interestingly, SRA expression in these two subgroups was significantly (Mann-Whitney rank-sum test, P < 0.05) lowe r than that observed in ER+/PR- (median = 156.4, n = 6) and ER-/PR+ (median = 144.8, n = 8) tumors. A variant form of SRA, presenting a deletion of 20 3 bp within the SRA core sequence, was also observed in breast tumor tissue s. The relative expression of this new SRA isoform correlated with tumor gr ade (Spearman coefficient r = 0.53, n = 27, P = 0.004). These data suggest that changes in the expression of SRA-related molecules occur during breast tumor progression.