# The Immunohistochemical Expression of REV-7 in Various Human Cancer Pathology Specimens: A Systematic Review

## TL;DR

This review summarizes how the protein REV-7 is expressed in various human cancers and its link to disease progression and treatment resistance.

## Contribution

This is the first systematic review to analyze REV-7's immunohistochemical expression across multiple cancer types and its clinical implications.

## Key findings

- REV-7 is expressed in cancers like testicular, ovarian, and breast cancer.
- High REV-7 levels correlate with faster disease progression and worse prognosis.
- REV-7 inactivation shows promise as a therapeutic strategy for resistant cancers.

## Abstract

The purpose of this systematic review is to summarize all existing evidence, regarding the immunohistochemical expression of REV-7 in different human cancer pathology specimens. Moreover, the association of REV-7 expression with disease severity (clinical course), patients’ survival, prognosis, and response to various treatments, such as chemotherapy and irradiation, was investigated. Three databases (PubMed, Scopus, and Cochrane) were systematically screened, from inception to September 2, 2023, as suggested by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Only studies using immunohistochemical staining for REV-7 in paraffin-embedded cancer tissues were included. Nine studies met the inclusion criteria and were included in the final qualitative synthesis. All nine studies were retrospective and non-comparative ones. Selected studies reported immunohistochemical expression of REV-7 in different types of cancer, including testicular cancer, ovarian cancer, esophagus squamous cell carcinoma, prostate cancer, colorectal cancer, diffuse large B-cell lymphoma, breast cancer, lung cancer, and skin cancer. High REV-7 expression was associated with faster disease progression, resistance to available treatment options, and worse prognosis in the majority of included studies. These results indicate that immunohistochemical staining of REV-7 protein could potentially be used as a predictive tissue marker in certain cases. Promising results, arising from REV-7 inactivation experiments, render REV-7 targeting a potential therapeutic strategy for future cancer management, especially in the cases of chemoresistant or radioresistant disease.