Ratio analysis of ERβ isoforms in paired cancerous and adjacent normal breast tissues / 肿瘤研究与临床

ABSTRACT

Objective To illustrate the composition ratio of ERβ isoforms in paired cancerous and adjacent normal tissues from breast cancer patients.Methods Eighty-seven pairs of cancerous and adjacent normal tissues were obtained from breast cancer patients.RT-qPCR was used to determine the relative mRNA expression levels of ERβ isoforms (ER[β1,ERβ2 and ERβ5),and the composition ratios of ERβ isoforms were analyzed.Results The expression levels of all tested ERβ isoforms (ERβ1,ERβ2 and ERβ5) in breast cancer tissues were much lower than those in adjacent normal breast tissues (P ＜ 0.01).Isoform ratio analysis showed that ERβ5 was the dominant isoform in both cancerous and adjacent normal tissues with a positive detection rate of 54.02 ％ and 75.84 ％,respectively.Meanwhile,ERβ1 had the lowest detection rate (9.74 ％ and 6.77 ％ in cancerous and adjacent normal tissues,respectively).The positive rates for both ERβ1 and ERβ2 were much lower in adjacent normal tissues than those in cancer tissues (Z =-2.24,P =0.025 and Z =-4.85,P ＜ 0.01,separately),while more cancerous tissues were ERβ5-positive in comparison to adjacent normal tissues (Z =-5.32,P ＜ 0.01).Conclusions The expression levels of all the ERβ isoforms are differentially down-regulated with significant alterations in their composition ratios during breast carcinogenesis.Further understanding on molecular mechanisms underlying the differential down-regulation of ER[β isoforms will shed new light on breast carcinogenesis.