Introduction

MAGI-2 (Membrane Associated Guanylate Kinases Inverted 2) is a scaffolding protein that interacts with PTEN in shutting off the Pi3K/AKT pathway. MAGI-2 suppresses AKT by enhancing PTEN function and its protein stability. In this study, we examined the protein expression of MAGI-2 in normal tissues and various solid tumors by immunohistochemistry (IHC).

Methodology

An IHC study of MAGI-2 was performed on normal tissue and tumor tissues from prostate (34 cases), ovary (95 cases), urinary bladder (92 cases), pancreas (88 cases), liver (2 cases), colon (2 cases), and lymphoma (185 cases). MAGI-2 staining intensity was semi-quantitatively scored using a 0-3 scale. Percent positive rate of MAGI-2 was calculated for carcinomas from prostate, urinary bladder, ovary, pancreas, liver, colon, and lymphoma.

Results

In normal tissues, MAGI-2 was detectable by IHC mostly in follicle area of the tonsil or lymph node and in the cuboidal or columnar epithelium of several organs (skin, urinary bladder, breast, fallopian tube, small intestine, colon, prostate, adrenal gland, and thyroid). The protein expression of MAGI-2 was higher in tumor cells than in their adjacent normal tissues from prostate, urinary bladder, ovary, pancreas, lymph node, liver, and colon. The positive rate of MAGI-2 was 100% for invasive prostate adenocarcinoma (34/34 cases), 82% for ovarian adenocarcinoma (78/95 cases), 76 % for urinary bladder carcinoma (70/92 cases), 62 % of pancreatic adenocarcinoma (55/88 cases), 83 % for diffuse large B-cell lymphoma ( 135/163 cases), 80 % for follicular B-cell lymphoma (8/10 cases), 67% for non-Hodgkin B-cell lymphoma (6/9 cases), 0% for small lymphocytic B-cell lymphoma (0/3 cases), 100% for colon adenocarcinoma (2/2 cases), and 100% for hepatocellular carcinoma (2/2 cases).

Conclusions

MAGI-2 is overexpressed in most lymphomas and carcinomas from prostate, urinary bladder, ovary, pancreas, liver, and colon, but it is not detectable in small lymphocytic B-cell lymphoma by IHC for this study.

Citation Format: Zhiming Liao. Immunohistochemical study of MAGI-2 expression in lymphomas and carcinomas from prostate, urinary bladder, ovary, pancreas, liver, and colon [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr LB-245. doi:10.1158/1538-7445.AM2017-LB-245