Efficacy and safety comparison between axillary lymph node dissection with no axillary surgery in patients with sentinel node-positive breast cancer: a systematic review and meta-analysis.

BACKGROUND: This systematic review and meta-analysis aimed to study the evidence on the efficacy and safety of omitting axillary lymph node dissection (ALND) for patients with clinically node-negative but sentinel lymph node (SLN)-positive breast cancer using all the available evidence. METHODS: The Embase, Medline, and Cochrane Library databases were searched through February 25, 2023. Original trials that compared only the sentinel lymph node biopsy (SLNB) with ALND as the control group for patients with clinically node-negative but SLN-positive breast cancer were included. The primary outcomes were axillary recurrence rate, total recurrence rate, disease-free survival (DFS), and overall survival (OS). Meta-analyses were performed to compare the odds ratio (OR) in rates and the hazard ratios (HR) in time-to-event outcomes between both interventions. Based on different study designs, tools in the revised Cochrane risk of bias tool were used for randomized trials and the risk of bias in nonrandomized studies of interventions to assess the risk of bias for each included article. Funnel plots and Egger's test were used for the publication's bias assessment. RESULTS: In total, 30 reports from 26 studies were included in the systematic review (9 reports of RCTs, 21 reports of retrospective cohort studies). According to our analysis, omitting ALND in patients with clinically node-negative but SLN-positive breast cancer had a similar axillary recurrence rate (OR = 0.95, 95% confidence interval (CI): 0.76-1.20), DFS (HR = 1.02, 95% CI: 0.89-1.16), and OS (HR = 0.97, 95% CI: 0.92-1.03), but caused a significantly lower incidence of adverse events and benefited in locoregional recurrence rate (OR = 0.76, 95% CI: 0.59-0.97) compared with ALND. CONCLUSION: For patients with clinically node-negative but SLN-positive breast cancer (no matter the number of the positive SLN), this review showed that SLNB alone had a similar axillary recurrence rate, DFS, and OS, but caused a significantly lower incidence of adverse events and showed a benefit for the locoregional recurrence compared with ALND. An OS benefit was found in the Macro subset that used SLNB alone versus complete ALND. Therefore, omitting ALND is feasible in this setting. TRIAL REGISTRATION: CRD 42023397963.

Clinical significance of epigenetic silencing and re-expression of O6-methylguanine-DNA methyltransferase using epigenetic agents in laryngeal carcinoma.

The aim of the present study was to investigate the association between O6-methylguanine-DNA methyltransferase (MGMT) gene expression levels, and DNA methylation status and histone modifications in laryngeal squamous cell carcinoma (LSCC). Chromatin immunoprecipitation, methylation-specific polymerase chain reaction (PCR), and reverse transcription-quantitative PCR were performed to analyze histone modifications, DNA methylation status and mRNA expression levels in the promoter region of the MGMT gene in laryngeal carcinoma HEp-2 cells, as well as in 50 paired healthy and LSCC tissue samples. The present study demonstrated that treatment of HEp-2 cells with 5-aza-2'-deoxycytidine (Aza), a DNA methyltransferase inhibitor, significantly upregulated MGMT mRNA expression levels, reduced MGMT DNA methylation, reduced MGMT histone H3 lysine 9 (H3K9) di-methylation, and increased MGMT histone H3 lysine 4 di-methylation without a significant change in H3K9 acetylation. Trichostatin A (TSA), a histone deacetylase inhibitor, marginally upregulated MGMT mRNA expression levels without affecting the DNA methylation status, or H3K9 or H3K4 di-methylation, however, TSA treatment caused a significant increase in H3K9 acetylation. Furthermore, Aza and TSA combination treatment produced a synergistic effect. In the LSCC samples, the rate of DNA methylation in the MGMT gene was 54%, compared with 24% in the healthy control group (P<0.05). Therefore, data from the present study indicates that MGMT may serve as a novel therapeutic target in the treatment of LSCC.