Treatment of prostate cancer cells with recombinant IL-6 was found to increase G6PD expression (Fig. 3I) and treatment of prostate cancer cells [either LNCaP or a bone-metastatic derivative, C4-2B (11)] with HS5 CM increased phosphorylation of signal transducer and activator of transcription 3 (STAT3), a known downstream mediator of IL-6 (Fig. 3, J and K). Here, STAT3 is linked to prostate cancer.