AR and pure red-cell aplasia: According to published reports, the expression pattern of the αVβ6 integrin is highly heterogeneous in primary prostate tumors; it is highly expressed in bone metastatic PrCa cases, whereas its expression is undetectable in neuroendocrine PrCa (NEPrCa) cases and normal prostatic epithelium.23,24,43 However, none of these studies examined the correlation between the αVβ6 integrin and AR expression in PrCa patients.