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proximal colon.2. The relationship between the incidence of CR- PaM and CENThe pathological examinations about the human colorectal tissue derived the endoscopical biopsies have revealed that the CR-PaM is higher in the proximal colon, and in the persons with CEN (50.8%, 60 / 118) than those with non-CEN (37.1%, 75 / 202) among 320 persons12).This our study was performed in the cooperation with many doctors (Miwa H, Kondo K, et al.) of the department of gastroenterology of Juntendo Univer-sity Hospital, 1980’s. CEN existed whole large bowel, not only the nearby region of CR-PaM. And these findings have pointed out that there is a relation-ship between the CR-PaM and the existence of CEN.3. Molecular biological investigations for CR-PaMVogelstein et al.13) have reported the involve-ment of multistage genetic abnormalities in the development of colorectal carcinomas, and pointed out that K-ras mutation is the initial genetic abnor-mality in the adenoma-carcinoma sequence14, 15) of the development of the colorectal carcinomas. Recently, some reports have pointed out that the The incidence of CRA-Pa in native Japanese was lower than those in Japanese descendants and Caucasian residents in Hawaii, and this finding was thought to show that the incidence of CRA-Pa is related to the lifestyle of European and American. And really, in the present time (in 2018) when the lifestyle of European and American has been established, the incidence CRA-Pa in native Japanese was increased and equal to those in Japanese descendants and Caucasian residents in Hawaii in the 1980’s. According to location, Paneth cells were more frequently observed in proximal colon of every race (P < 0.01, Chi-squared analysis).CRA-Pa : Colorectal adenoma with Paneth cell, C : cecum(caecum), A : ascending colon, T : transverse colon, D : descending colon, S : sigmoid colon, R : rectum.424Figure 3　The incidence of large bowel adenoma with Paneth cellsreplication errors and loss of heterozygosity of the microsatellite markers have the development of the colorectal carcinomas16, 17).We have reported that the frequencies of the K-ras codon 12 mutations (K-ras) and the loss of heterozygosity of dinucleotide microsatellite markers (LOH-MS) in the propria mucosa with CR-PaM of the right colon18).Our results in this report revealed that 1. K-ras mutation was detected in fifteen regions among 52 CR-PaM (28.9%). All mutations were a single mutation. For K-ras mutation patterns, 11 showed GGT to AGT, and four showed to GAT. 2. LOH-MS was detected in twenty-one regions among 52 CR-PaM (40.4%) (D2S123: 35.4%, 17/48 regions, D17S250 : 13.7%, 7/51 regions, and D5S346: 0%, 0/52 regions).No K-ras mutations and LOH-MS were detected in the contorols (Colorectal mucosa with no CR-PaM, no neoplastic lesion, no aberrant crypt foci and no hyperplastic polyp). Thus, the frequency of both K-ras mutation and LOH-MS in the colonic mucosa with PaM were significantly higher than those of the controls (p<0.01, chi-square test).That is say, some of CR-PaM have the gene abnormalities connected with the development of