O.J. Simpson has reportedly been diagnosed with prostate cancer and is undergoing chemotherapy, RadarOnline.com has learned. The 76-year-old is not in hospice and appeared in good spirits on Friday after the news broke. While the ex-NFL legend laughed off the hospice rumors, he did not deny his health battle. Sources shared Simpson’s alleged diagnosis and treatment with Local 10 News, revealing he’ll be fighting his reported cancer battle in Las Vegas. Simpson — who was famously acquitted of murdering his ex, Nicole Brown Simpson, and her friend,Ron Goldman, in the ’90s — took to social media …