PMC9713776_01
Clinicopathological features of the analyzed patient. (A) The left panel shows the initial endoscopic findings. Multiple LST-NG lesions (arrowheads) were identified in the entire large intestine. The right panel shows that one of the LST-NG lesions developed into an adenocarcinoma in the sigmoid colon (arrows) during the 4-year annual endoscopic surveillance. (B) A surgical specimen of the large intestine had >150 LST-NG lesions and a cancer lesion. One normal mucosa, four LST-NG lesions (L1-L4) and one cancer lesion were collected and analyzed. (C) Histopathology of an LST-NG lesion and a sigmoid adenocarcinoma (arrows) (scale bar, 3-mm). LST-NG, laterally spreading tumor-nongranular type lesions.
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A+B calcium (Fig. 1A). All the flat lesions were LST-NG, and the biopsy samples obtained from the lesions were pathologically diagnosed as tubular adenomas. After 4 years of annual endoscopic surveillance, one of the LST-NG lesions had developed into an adenocarcinoma in the sigmoid colon (Fig. 1A). The postoperative histopathology results demonstrated the presence of a tubular adenocarcinoma and multiple tubular adenomas (Fig. 1B and C).
Methylation profile focused on DMSs in the analyzed patient. (A) Clustered heatmap composed of 766 DMSs. For each CpG site in the CpG islands of the gene region, a DiffScore value of >100 between the normal mucosa and the cancer was defined as the absolute DMS value of the sample. In the majority of DMSs, the methylation levels of the LST-NG lesions were the same as those of the normal mucosa (Group a). However, there were small clusters with methylation levels as high as those of the cancer lesion (Group b). (B) Heatmap focused on Group b with information about each DMS. DMSs, differentially methylated sites; ZNF625, zinc finger protein 625; LONRF2, LON peptidase N-terminal domain and ring finger 2; MSC, musculin; OPLAH, 5-oxoprolinase, ATP-hydrolysing; PCDHGA4, protocadherin gamma subfamily A, 4; GSG1L, GSG1 like; BEND5, BEN domain containing 5; SDC2, syndecan 2; WDR17, WD repeat domain 17.
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Among the 766 detected DMSs, we selected one methylated CpG site from each of the cancer and normal mucosa samples, and performed clustering analysis of the normal mucosa sample, four LST-NG lesions, and cancer sample, as shown in Fig. 2A. DMS levels of the LST-NG lesions were as high as those in the cancer sample (Fig. 2B). DMS occurred at the CpG islands of the following nine genes: ZNF625, LONRF2, MSC, OPLAH, PCDHGA4, GSG1L, BEND5, SDC2, and
Methylation profile focused on CpG island regions including DMSs categorized in group b. The methylation values of the CpG island regions around the DMS site in Group b were determined. In the cancer lesions, all the CpG island regions, including each DMS, were methylated in all nine genes, and the CpG sites of ZNF625, LONRF2, MSC and OPLAH were methylated in all four LST-NG lesions. SDC2 and WDR17 were methylated in three LST-NG lesions. In the CpG islands in GSG1L, BEND5 and PCDHGA4, the CpG sites were not methylated as cancer lesions. TSS200, 200 bases upstream of the TSS; TSS500, 500 bases upstream of the TSS; TSS1500, 1,500 bases upstream of the TSS; 5'UTR, within the 5' untranslated region, between the TSS and the ATG start site; body, between the ATG and stop codon. TSS, transcriptional start site; DMSs, differentially methylated sites; LST-NG, laterally spreading tumor-nongranular type lesions; ZNF625, zinc finger protein 625; LONRF2, LON peptidase N-terminal domain and ring finger 2; MSC, musculin; OPLAH, 5-oxoprolinase, ATP-hydrolysing; PCDHGA4, protocadherin gamma subfamily A, 4; GSG1L, GSG1 like; BEND5, BEN domain containing 5; SDC2, syndecan 2; WDR17, WD repeat domain 17.
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WDR17. We further checked the methylation values at the CpG islands including the DMS site detected in Group b (Fig. 3).