Table 1.

Comparison of Ki-67 and cytokeratin 20 (CK20) staining in atypical and typical hyperplastic polyps

Staining pattern	Typical on light microspopy (n=26)	Atypical on light microspopy (n=31)
Usual pattern (Ki-67 positivity confined to lower crypt, CK positivity confined to upper crypt)	17	11
Upper crypt zone Ki-67 positivity, usual pattern CK20 positivity	1	2
Usual pattern Ki-67 positivity with basal CK20 positivity	7	14
Upper crypt zone Ki-67 positivity and basal CK20 positivity	1	4
p=0.036 for CK20 differences (Fisher's exact test; p value for the same or stronger association); p=0.19 for Ki-67 differences (Fisher's exact test; p value for the same or stronger association).