Human Epidermal Growth Factor Receptor 2 Expression in Prostatic Carcinomas: A Systematic Review and Meta-Analysis of...

The clinical relevance of HER2 expression profile in solid cancers has expanded with the evolving landscape of HER2 targeting agents. This systematic review and meta-analysis aim to detail the prevalence of HER (over)expression in prostate cancer and identify patient/disease subgroups with enriched HER2 overexpression.

Literature searches of five databases were performed. HER2 scores with cross-tabulation of clinicopathological parameters were extracted for pooled prevalence and odds ratio analyses. Study quality, heterogeneity, and publication bias were assessed by the CASP checklist, I² index, and LFK index.

In total, 16 studies were included with 1258 cases. There were 669 (53.18%), 269 (21.38%), 250 (19.87%), and 70 (5.56%) of HER2 Scores 0/1/2/3, respectively. Pooled analysis indicated a prevalence of 4.9% (95% CI 3.0%-7.2%) for HER2 Score 3 and 42.0% (95% CI 29.0%-55.6%) for HER2 non-negative (Scores 1-3). Subgroup analysis comparing HER2 negative (0, 1) and HER2 overexpression (3) indicated higher Gleason score (OR = 0.061, 95% CI: 0.010-0.359, p < 0.001), higher disease stage (OR = 0.063, 95% CI: 0.016-0.252, p < 0.001) and biopsies from metastatic site (OR: > 100, 95% C.I.: > 100-> 100, p < 0.001) favoring HER overexpression, without significant differences for patient age or prostate-specific antigen (PSA) level. I² was 91.63% with meta-regression analysis showing study quality as a source of heterogeneity (p = 0.043). LFK index was 1.93 (moderate publication bias risk, p = 0.054).

HER2 overexpression is rare in prostatic carcinomas but nearly half show HER2 expression of Score 1 or above. Cases with higher Gleason score and advanced disease stage are more likely to overexpress HER2.