In vitro exposure of malignant prostate cell lines to ascorbic acid-menadione showed that tumor cells were killed through a mechanism named autoschizis. Experimental animal studies showed that autoschizis is also evident when ascorbic acid-menadione is administered to nude mice with implanted human prostate tumors. Prostate-specific antigen (PSA) is a known serum marker of prostate tumor cells specific activity. Recently, total serum homocysteine has been identified as a marker of tumor cell numbers with sensitivity for early detection of tumor cell death induced by treatments. A clinical trial with prostate cancer patients submitted to the association of ascorbic acid-menadione was performed and PSA/homocysteine was assessed in the follow-up. The early response in serum PSA and homocysteine levels was reported. The results showed that ascorbic acid-menadione produced an immediate drop in tumor cell numbers as assessed by homocysteine levels. Serum PSA levels showed an early rise and later dropped. These results suggest that autoschizis can also be induced by this pharmacological association at the clinical level in prostate cancer patients. Further studies are being performed in order to research if these results can be found with other primary tumors as it was shown in in vitro and experimental models. Ascorbic acid-menadione could be emerging as a new anti-tumoral chemotherapy.