Smac/DIABLO immunostaining correlates with local recurrence in squamous carcinoma. (A) and (C): Smac/DIABLO immunostained area. (B) and (D): Smac/DIABLO intensity of immunostaining. Scores were calculated as described in Material and Methods. Graphs show median, upper and lower quartiles. P value testing the significance of the difference was determined by Chi square test.