S2060 Aberrant Expressions of Gastric Type Mucin and Claudin in Colorectal Serrated Polyps

Abstract

F ratio of intestinal type cancer was 3.41 at age less than 50, reached a peak of 7.86 at age 50-59, and then showed a progressive decrease with a minimum of 2.29 at age group 80 years and over. In contrast, the crude incidence rate of diffuse-type adenocarcinoma was similar in males and females (5.58 vs. 5.20 /100, 000/ year) yielding M/F of 1.07. Curve modelling of the age-specific rates for diffuse subtypes showed similar equations, y = 0.016 x mean age 2.007 +32.98, R2 = 0.999 and y = 0.016 x mean age 1.954+35.97, R2 = 0.989, for male and females, respectively. For the intestinal histological type, the age-specific incidence rates were different for males and females. Curve modelling indicated the same kinetic equation for rise in incidence with age, in males (y = 0.016 x mean age 2.315+28.75, R2 = 0.990) and in females (y = 0.016 x mean age 2.316+46.07, R2 = 0.998). However, the female curve was displaced to the right indicating a delay in the cancer onset. The estimated cancer onset delay for females was 17.2 years (i.e. +46.07 minus +28.75= 17.22). Conclusion Male predominance in upper GI adenocarcinomas is a reflection of approximately 2 decades delay of development of intestinal subtype adenocarcinoma in females. The mechanism of the marked delay in development of intestinal subtype requires elucidation.