USP7 and Familial prostate cancer: Moreover, the pharmacological inhibition of the de-ubiquitinase USP7 also affects the growth of castration resistance prostate cancer cells, 22Rv1, that express both functional AR full lenght and its constitutive variant isoform V7, reducing the levels of the variant V7, possible driven by the ability to heterodimerize with the full lenght androgen receptor [39].