As illustrated in Figure 5B, RT-PCR analyses indicated that A2M mRNA expression was abundant in endometrioid carcinomas (lane 2, -3, -6, and -7), which is characterized by glandular patterns resembling those of the endometrium, but there was little or no expression of A2M in serous, mucinous or clear cell carcinomas and normal ovaries (please see Additional file 3, Supplemental Figure S3). Here, A2M is linked to clear cell adenocarcinoma.