AUTHOR=Yoon Ju-Yoon , Wang Julia Y. , Roehrl Michael H. A. 

TITLE=An Investigation Into the Prognostic Significance of High Proteasome PSB7 Protein Expression in Colorectal Cancer

JOURNAL=Frontiers in Medicine

VOLUME=Volume 7 - 2020

YEAR=2020

URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2020.00401

DOI=10.3389/fmed.2020.00401

ISSN=2296-858X

ABSTRACT=Using unbiased proteomics, we had previously discovered that the catalytic proteasome subunit β type 7 (PSB7) protein is frequently overexpressed in colorectal adenocarcinomas. In this paper, we validate this finding and derive a prognostic significance for PSB7 by examining an expanded, well-annotated clinical cohort of 318 colorectal cancer patients. We found PSB7 protein levels to be similarly increased in both advanced stage primary disease and metastatic lesions. We then examined the prognostic value of PSB7 protein expression. Elevated PSB7 protein as well as PSMB7 mRNA levels showed trends for association with lower overall survival, particularly in female patients. The prognostic value of elevated PSB7 protein levels was highest for female patients who were older (≥60 years of age at diagnosis) or who had received adjuvant chemotherapy. Multivariate analyses that included pT stage, tumor grade, tumor size, and tumor site supported these findings. Thus, PSB7 protein upregulation is an independent predictor of poor overall survival in colorectal cancer among older female patients, especially those treated with adjuvant chemotherapy.