MMP9 and Arthritis: Entering these individual neoplasia predictive factors into a logistic regression model (Table 3), along with potential confounding factors such as recent injuries, arthritis, muscular problems (which may have affected observed MMP9 measurements) and bearing in mind the expected prevalence of 6%, a cutoff on the predicted probability of neoplasia of 0.05 (5%) resulted in a sensitivity of 79% and specificity of 63%.