Significant increase of colonic mutated crypts correlates with age in sporadic cancer and diverticulosis cases, with higher frequency in the left‐ than right‐side colorectum

Abstract

Mild periodic acid-Schiff (mPAS) staining can discriminate non-Oacetylated (mPAS-positive) from O-acetylated (mPAS-negative) epithelial sialoglycoproteins in human colonic mucosa, allowing the three haplotypes expressed from a single polymorphic autosomal gene (oat) to be distinguished. In heterozygotes, we previously demonstrated wholly mPAS-positive (stem cell mutated ) crypts and clusters of two or more mPAS-positive crypts to be significantly increased with duration of ulcerative colitis. To establish whether such an increase in the number of mutated crypts with age also occurs in normal individuals or in cases with diverticulosis, the O-acetylation phenotype in the non-cancerous colonic mucosa of 47 sporadic colorectal cancer patients who were heterozygotes for oat was tested with mild-PAS staining. PAS-positive crypts were assessed histologically in relation to age and compared between the left (sigmoid colon and rectum) and right (cecum and ascending colon) sides of the colorectum. I t is widely accepted that the likelihood of developing sporadic colorectal carcinoma increases with age.(1-3) Colorectal tumorigenesis is a multistage process, (4) with increased colonic mucosal cell proliferation believed to be important for initiation and subsequent growth, (5,6) acting together with the cumulative effects of protracted exposure to cancer-causing agents. Recently, it was demonstrated that mPAS staining can discriminate non-O-acetylated (mPAS-positive) from O-acetylated (mPASnegative) epithelial sialoglycoproteins. . In fact, the frequency distribution of these three phenotypes in different racial groups, including Japanese and British people, is consistent with that predicted by the Hardy-Weinberg law. (8) This suggests that they result from expression of a single polymorphic autosomal gene (oat) encoding the O-acetyl transferase active in generating colonic sialomucins. Further, the three phenotypes are similar to those seen in C57BL/6 J × SWR F1 mice, where the Dlb-1 gene determines another intestinal mucus glycoprotein phenotype that can be visualized by virtue of Dolichos biflorus agglutinin binding. (9) In this mouse model, discordant crypts are produced in heterozygotes by mutation. The altered crypts seen in humans using the mPAS technique are also similar in morphology to carcinogen-induced crypts with changes in glucose-6-phosphate dehydrogenase expression in the mouse colon, indicating a role for somatic mutations. (10) It is conceivable that somatic mutations of the high acetylator allele in colonic crypt stem cells in heterozygous subjects followed by crypt colonization by mutant progeny leads to conversion of the crypt phenotype from mPAS negative to mPAS positive. In fact, radiotherapy of heterozygotes induces a considerable increase in the mPAS-positive crypt frequency, which subsequently remains significantly elevated for 2-34 years, indicating that crypts with a mutant phenotype are stable. (11,12) Recently, we demonstrated that the number of wholly mPASpositive (stem cell mutated) crypts a...

Development of ulcerative colitis and its associated colorectal neoplasia as a model of the organ‐specific chronic inflammation‐carcinoma sequence

“…With the same method, a correlative increase in the number of mPAS‐positive mutated crypts and clusters of two or more mutated crypts with age also was observed in the non‐cancerous colonic mucosa of sporadic colorectal cancer and diverticulosis patients, with higher frequency in the left‐ than right‐side colon. However, appearance of mutated crypts with the duration of UC illness is much higher than those in non‐UC cases with age 39 . Interestingly, a coefficient line in correlation of frequency of wholly mPAS‐positive crypts with age showed zero mPAS‐positive crypts at 0 years old in non‐cancerous colonic mucosa of sporadic colorectal cancer patients, indicating appearance and gradual increase of colonic mutated crypts after birth in human life.…”

“…However, appearance of mutated crypts with the duration of UC illness is much higher than those in non-UC cases with age. 39 Interestingly, a coefficient line in correlation of frequency of wholly mPAS-positive crypts with age showed zero mPAS-positive crypts at 0 years old in non-cancerous colonic mucosa of sporadic colorectal cancer patients, indicating appearance and gradual increase of colonic mutated crypts after birth in human life.…”

Comparative lesion sequencing provides insights into tumor evolution

“…This approach yields T pot , defined as the time between cell divisions in the absence of cell death. Several hundred colorectal cancers have been evaluated by this method, with T pot measured as Ϸ4 days (16)(17)(18)(19)(20)(21). By using this figure for the cell division rate and the mutational data reported in ref.…”

Appearance of epithelial and stromal genomic instability in background colorectal mucosa of sporadic colorectal cancer patients: relation to age and gender

“…Previously, we reported that the significant increase of colonic mutated crypts correlated with age in the background mucosa of sporadic colorectal cancer cases using the mild periodic acid-Schiff (m-PAS) staining method [22]. Further, the stem cell mutated crypts were significantly increased with the duration of the illness of ulcerative colitis, which possibly indicates the accumulation of genomic mutations in the chronic inflammation-carcinoma sequence [23].…”