Decreased ABCG2 expression in prostate cancer and negatively associated with poorly differentiated grade and biochemical recurrence

Abstract EN

Summary Few prognostic biomarkers have been identified for prostate cancer and there are clinical difficulties in distinguishing between relapsing and non-relapsing diseases.

The aim of this study is to investigate the hypothesis that ABCG2 might be a potential biomarker for prostate cancer and could distinguish between aggressive tumours requiring radical intervention and those that have a good prognosis.

ABCG2 is a transmembrane protein that plays a vital role in promoting proliferation and maintaining the undifferentiated phenotype of stem cells.

It is thought to be a potential biomarker that can predict clinical progression and prognosis of different kinds of tumors.

However, its role in prostate tumor remains unclear.

Nuclear and cytoplasmic ABCG2 staining has been evaluated by immunohistochemistry using two sources of patient samples.

The tissue microarray group consists of 96 cases including normal, adjacent normal and malignant prostate tissue samples.

The Bath cohort consists of 30 samples, including samples from patients that had recurrent disease and those who remained disease-free.

The immunohistochemical study showed nuclear and cytoplasmic ABCG2 expression in benign and malignant prostate samples.

Cytoplasmic ABCG2 expression was also significantly reduced in prostate cancer compared to normal tissues.

Cytoplasmic ABCG2 staining was negatively associated with increasing Gleason grade.

In the Bath cohort, there was a negative association between ABCG2 expression and biochemical relapse.

This preliminary data showed that ABCG2 might play a role in cancer formation and/or aggressiveness and warrants further investigation to understand its function and establish if it could be a potential diagnostic biomarker for prostate tumour.