This invention relates to a method for assessing risk of prostate cancer. Specifically, it relates to utilizing both Pro108 and Prostate Specific Antigen (PSA) in combination to determine the risk of prostate cancer. In addition, it is directed to a method for assessing risk of ovarian, colon, breast or stomach cancer utilizing Pro108 or specific antibodies to Pro108. The invention provides isolated anti-prostate, ovarian, colon, breast or stomach cancer antigen (Pro108) antibodies that bind to Pro108 on a mammalian cell in vivo. The invention also encompasses compositions comprising an anti-Pro108 antibody and a carrier. These compositions can be provided in an article of manufacture or a kit. Another aspect of the invention is an isolated nucleic acid encoding an anti-Pro108 antibody, as well as an expression vector comprising the isolated nucleic acid. Also provided are cells that produce the anti-Pro108 antibodies. The invention encompasses a method of producing the anti-Pro108 antibodies. Other aspects of the invention are a method of killing an Pro108-expressing cancer cell, comprising contacting Pro108 present in the ECM with an anti-Pro108 antibody and a method of alleviating or treating an Pro108-expressing cancer in a mammal, comprising administering a therapeutically effective amount of the anti-Pro108 antibody to the mammal.