TKT and metastatic prostate carcinoma: In another study, a relatively interesting therapeutic approach has been employed, involving the use of Herpes Simplex Virus Thymidine Kinase (HSV-TK)/ganciclovir (GCV) system (HSV-TK/GCV) fused with the Connexin 43 (Cx43) gene in suicide gene therapy and gemcitabine to enhance the anticancer effect in the treatment of locally advanced or metastatic prostate cancer.