Relation between mismatch repair status, chemoresponse, survival and anatomic location in gastroesophageal adenocarcinoma

BACKGROUND

It has recently been reported that mismatch repair (MMR) status and microsatellite instability (MSI) status in gastroesophageal carcinomas predict surgical, chemotherapeutic and immunotherapeutic outcomes; however, there is extensive variability in the reported incidence and clinical implications of MMR/MSI status in gastroesophaegal adenocarcinomas. We characterized a Canadian surgical patient cohort with respect to MMR status, clinicopathologic correlates and anatomic tumour location.

METHODS

We investigated MMR and BRAF V600E status of gastroesophaegal adenocarcinomas in patients who underwent gastrectomy or esophagectomy with extended (D2) lymphadenectomy at a single centre between 2011 and 2019. We correlated patterns of MMR expression in the overall cohort and in anatomic location-defined subgroups with treatment response and overall survival using multivariate analysis.

RESULTS

In all, 226 cases of gastroesophaegal adenocarcinoma (63 esophageal, 98 gastroesophageal junctional and 65 gastric) were included. The MMR-deficient (dMMR) immunophenotype was found in 28 tumours (12.3%) (15 junctional [15.3%], 13 gastric [20.0%] and none of the esophageal). The majority (25 [89%]) of dMMR cases showed MLH1/PMS2 loss without concurrent BRAF V600E mutation. Two MSH2/ MSH6-deficient gastric tumours and 1 MSH6-deficient junctional tumour were detected. The pathologic response to preoperative chemotherapy was comparable in the dMMR and MMR-proficient (pMMR) cohorts. However, dMMR status was associated with significantly longer median overall survival than pMMR status (5.8 yr v. 2.4 yr, hazard ratio [HR] 1.91, 95% confidence interval [CI] 1.06-3.46), particularly in junctional tumours (4.6 yr v. 1.9 yr, HR 2.97, 95% CI 1.27-6.94).

CONCLUSION

Our study shows that MMR status has at least prognostic value, which supports the need for biomarker testing in gastroesophageal adenocarcinomas, including junctional adenocarcinomas. This highlights the clinical significance of determining the MMR status in all adenocarcinomas of the upper gastrointestinal tract. Response to induction chemotherapy, however, was not influenced by MMR status.

Assessment of vascular function in Mexican women exposed to polycyclic aromatic hydrocarbons from wood smoke

The use of solid fuels for cooking and heating is likely to be the largest source of indoor air pollution on a global scale; these fuels emit substantial amounts of toxic pollutants such as polycyclic aromatic hydrocarbons (PAHs) when used in simple cooking stoves (such as open "three-stone" fires). Moreover, indoor air pollution from biomass fuels is considered an important risk factor for human health. The aim of this study was to evaluate the relationship between exposure to PAHs from wood smoke and vascular dysfunction; in a group of Mexican women that use biomass combustion as their main energy source inside their homes. We used 1-hydroxypyrene (1-OHP) as an exposure biomarker to PAHs and it was assessed using high performance liquid chromatography. The endothelium-dependent vasodilation was assessed through a vascular reactivity compression test performed with a pneumatic cuff under visualization of the brachial artery using high resolution ultrasonography (HRU). Assessment of the carotid intima-media thickness (CIMT) was used as an atherosclerosis biomarker (also assessed using HRU); and clinical parameters such as anthropometry, blood pressure, glucose, triglycerides, total cholesterol, HDL cholesterol, LDL cholesterol, among others were also evaluated. The mean concentration of urinary 1-OHP found in exposed women was 0.46±0.32μmol/mol Cr (range: 0.086-1.23μmol/mol Cr). Moreover, vascular dysfunction (diminished endothelium dependent vasodilation) was found in 45% of the women participating in the study. Association between vascular function and 1-OHP levels was found to be significant through a logistic regression analysis (p=0.034; r(2)=0.1329). Furthermore, no association between CIMT and clinical parameters, urinary 1-OHP levels or vascular dysfunction was found. Therefore, with the information obtained in this study, we advocate for the need to implement programs to reduce the risk of exposure to PAHs in communities that use biomass fuels as a main energy source.