Objective:This study aims to analyze the occurrence rate, positive rate, and other related factors influencing interpec-toral lymph nodes (IPNs) in breast cancer patients. This work further aims to explore the significance and indications of the surgical dis-section of IPNs. Methods:Clinical and pathological data from 1673 breast cancer patients were retrospectively analyzed. All patients were subjected to modified radical mastectomy, and IPNs were pathologically examined. The occurrence rate and metastasis of IPNs were recorded, and the relationship between the IPN positive rate and tumor size, axillary nodes, clinical stages, neo-adjuvant chemo-therapy, hormone receptors, Her-2 expression, and molecular subtypes of breast carcinoma was determined. Results:The occurrence rate, overall metastasis rate, and the positive rate of IPNs in patients with axillary lymph node metastasis were 13.39%, 4.30%, and 10.01%, respectively. IPN metastasis was significantly correlated with axillary node metastasis and the tumor, node and metastasis (TNM) stage of tumors (P<0.05). However, IPN metastasis was not significantly related with hormone receptor and Her-2 expressions. IPN metastasis rate may be unaffected by neo-adjuvant chemotherapy. Patients with IPNs metastasis were characterized by larger tu-mors, more positive axillary lymph nodes, and later TNM stages. Conclusion:IPN metastasis usually occurs in patients with larger tu-mors, more positive axillary lymph nodes, later TNM stages, as well as those with locally advanced cancer that meet the standard of neo-adjuvant chemotherapy. These indications suggest that the surgical dissection and pathological examination of IPNs should be rou-tinely performed.

Objective To investigate the effects and mechanism of TET2 inhibitor itaconate in prolifer-ation and migration of breast cancer cell line MDA-MB-231.Methods The MDA-MB-231 cells were treated for 24 h with dimethyl sulfoxide(DMSO)and 1,5 μmol/L itaconate respectively.The cellular apoptosis was determined by flow cytometry to determine the available itaconic acid concentration.The immunofluorescence was performed to determine the inhibiting effect of itaconate on hydroxymethylcytosine(5hmC)expression level.The cell counting and MTS were performed to determine the effect of itaconate on cell proliferation and activity.The Transwell experiment was performed to determine the effect of itaconate on cell transfer ability.The methylation-specific real-time fluorescence quantitative PCR(qPCR)was used to detect the effects of ita-conic acid treatment on the methylation of promoter regions of genes related to cell proliferation and migra-tion.qPCR was used to detect the effects of itaconate on the cellular proliferation,migration related genes ex-pression.Results 5 μmol/L itaconate treating the cells had no significant effect on the cellular apoptosis,mo-reover could inhibit 5hmC expression level.The cell count and MTS results showed that itaconate could pro-mote the cell proliferation(increase by about 58％,P＜0.05)and increase the cell activity(increase by 42％,P＜0.05).The Transwell experiment results showed that itaconate increased the cell migration(increase by 55％,P＜0.05).The methylation-specific qPCR showed that the itaconate treatment significantly promoted the methyaltion of the promoters p21 and PTEN.The qPCR results showed that itaconate significantly inhibi-ted the expression levels of p21 and PTEN(P＜0.05).Conclusion Itaconate promotes the proliferation and migration of MDA-MB-231 cells through inhibiting 5hmC level of p21 and PTEN and decrease its expression.