Differences in K-ras and mitochondrial DNA mutations and microsatellite instability between colorectal cancers of Vietnamese and Japanese patients

[Background]:The incidence of early-onset (under 50 years of age) colorectal cancer (CRC) in the Vietnamese has been reported to be quite higher than that in the Japanese. To clarify the differences in genetic alterations between Vietnamese and Japanese CRCs, we investigated mutations in K-ras and mitochondrial DNA (mtDNA) and high-frequency microsatellite instability (MSI-H) in the CRCs of Vietnamese and Japanese patients. [Methods]:We enrolled 60 Vietnamese and 233 Japanese patients with invasive CRCs. DNA was extracted from formalin-fixed, paraffin-embedded tissue sections. K-ras mutations were examined with PCR-single-strand conformation polymorphism analysis. mtDNA mutations and MSI-H were examined with microsatellite analysis using D310 and BAT-26, respectively. [Results]:K-ras mutations were examined in 60 Vietnamese and 45 Japanese CRCs. The frequency of the mutations in the Vietnamese CRCs was significantly higher than that in the Japanese CRCs (8 of 24 [33%] vs 5 of 45 [11%], p =0.048). MSI-H was examined in 60 Vietnamese and 130 Japanese CRCs. The frequency of MSI-H in the Vietnamese CRCs was also significantly higher than that in the Japanese CRCs (6 of 27 [22%] vs 10 of 130 [8%], p =0.030). mtDNA mutations were examined in 60 Vietnamese and 138 Japanese CRCs. The frequency of mtDNA mutations in the Vietnamese CRCs was significantly higher than that in the Japanese CRCs (19 of 44 [43%] vs 11 of 133 [9%], p <0.001). There were no significant differences in clinicopathologic characteristics, such as age, sex, tumour location, and depth, in terms of tumours with/without each genetic alteration in the CRCs of the Vietnamese and Japanese patients. [Conclusions]:These results indicate that the developmental pathways of CRCs in the Vietnamese may differ from those of CRCs in the Japanese

Metachronous multiple esophageal squamous cell carcinomas and Lugol-voiding lesions after endoscopic mucosal resection

Background and study aims: Endoscopic mucosal resection (EMR) has been applied to the treatment of superficial esophageal squamous cell carcinoma (SCC). The incidence and characteristics of metachronous multiple esophageal SCCs and Lugol-voiding lesions (LVLs) were investigated in a retrospective study in patients who had undergone EMR for superficial esophageal SCC. Patients and methods: 96 patients with esophageal SCC who had been treated by EMIR were followed up by endoscopy for 12 months or longer. Clinicopathologic parameters such as tumor size and location and presence of LVLs were examined. Results: 10 patients (10%) had synchronous multiple SCCs, and 12 (13%) developed metachronous multiple SCCs. The mean annual incidence of newly diagnosed tumor was 4.4%. The incidence of a speckled pattern of LVLs was 20/74 (27%) in patients with solitary SCC, 5/10 (50%) in synchronous multiple SCC, and 10/12 (83%) in metachronous multiple SCC. The incidence of the presence of speckled pattern of LVLs was significantly higher in patients with multiple SCCs than in those with solitary SCC (68% vs. 27%, P = 0.0004). Conclusions: Patients who have undergone EMR for esophageal SCC, especially those with metachronous multiple LVLs in the background mucosa, should undergo follow-up with close endoscopic observation using Lugol staining