Yes, the SIBO raises the "set point of inflammation" throughout the body.  The high PSA is a response to inflammation processes and a predictor of cancer overall. ALSO, the bacteria in the gut communicate and are often in cahoots with bacteria in other parts of the body. A primary reason for elevated PSA is low-grade bacterial infection in the prostate, so there can be a self-supportive process; e.g. if the immune system is ignoring the bacteria in the small intestines and allowing overgrowth, then it can also be unresponsive to bacterial overgrowth in the prostate.