Esophageal squamous cell carcinoma (ESCC) is one of the most fatal types of malignant tumors worldwide. Epitranscriptome, such as N6‐methyladenosine (m6A) of mRNA, is an abundant post‐transcriptional mRNA modification and has been recently implicated to play roles in several cancers, whereas the significance of m6A modifications is virtually unknown in ESCC. Analysis of tissue microarray of the tumors in 177 ESCC patients showed that higher expression of m6A demethylase ALKBH5 correlated with poor prognosis and that ALKBH5 was an independent prognostic factor of the survival of patients. There was no correlation between the other demethylase FTO and prognosis. siRNA knockdown of ALKBH5 but not FTO significantly suppressed proliferation and migration of human ESCC cells. ALKBH5 knockdown delayed progression of cell cycle and accumulated the cells to G0/G1 phase. Mechanistically, expression of CDKN1A (p21) was significantly up‐regulated in ALKBH5‐depleted cells, and m6A modification and stability of CDKN1A mRNA were increased by ALKBH5 knockdown. Furthermore, depletion of ALKBH5 substantially suppressed tumor growth of ESCC cells subcutaneously transplanted in BALB/c nude mice. Collectively, we identify ALKBH5 as the first m6A demethylase that accelerates cell cycle progression and promotes cell proliferation of ESCC cells, which is associated with poor prognosis of ESCC patients.

Background/Aim: The potential advantages of robot-assisted thoracoscopic esophagectomy (RATE) have yet to be verified. This study focused on the degree of lymph node dissection around the left recurrent laryngeal nerve (RLN). Patients and Methods: A total of 21 consecutive patients who received RATE (RATE group) and 38 who received conventional thoracoscopic esophagectomy (TE) (TE group), both with extended lymphadenectomy, for thoracic squamous cell esophageal carcinoma, were enrolled in this study. We compared the numbers of lymph nodes dissected from the mediastinum, especially around the left RLN. Results: The median number of lymph nodes dissected from around the left RLN was 6 in the RATE group and 4 in the TE group, and the ratio of the dissected lymph nodes around the left RLN to all lymph nodes was significantly higher in the RATE group (p=0.048). Conclusion: Our findings indicate that a robotassisted surgical system enables for more extensive dissection of lymph nodes around the left RLN.

Decreased PMI correlates well with a poor prognosis in patients with ESCC. Changes in PMI over a period of time may have greater sensitivity when evaluating prognosis than the PMI at any single time point.

Background: Poor oral health is a risk factor for causing upper aerodigestive tract tumors, including esophageal cancer. Our aim was to determine the periodontitis rate in our cohort of esophageal cancer patients. We also analyzed whether preoperative dental examination and care reduces the likelihood of severe pneumonia after esophagectomy. Study Design: Between 2003 and 2014, 529 esophageal cancer patients received esophagectomy at Akita University Hospital. We studied 232 patients who had preoperative dental examinations and care (dental care group) retrospectively and assessed the severity of their periodontitis. The dental care group was compared to 297 patients who did not have preoperative dental care (control group) with respect to the incidence of severe pneumonia after esophagectomy. Results: Ninety-one patients (39.2%) in the dental care group were diagnosed with slight periodontitis and 69 (29.7%) were diagnosed with severe periodontitis. Among all the patients, 69 patients (13.0%) were diagnosed with grade 3B postoperative severe pneumonia. The dental care group had a significantly lower incidence of severe pneumonia than the control group. Moreover, multivariable logistic regression analysis revealed that anastomotic leakage, preoperative dental care, gender and %VC were correlated significantly with the occurrence of postoperative severe pneumonia. Conclusion: Preoperative dental examination and care by a dentist are essential to reduce the likelihood of postoperative severe pneumonia in esophageal cancer patients.