Prognostic significance of low HER2 expression in gastric cancer: a retrospective, single-center analysis.

INTRODUCTION: Mutated human epidermal growth factor receptor 2 (HER2) is an oncogene with critical pathogenic roles in breast cancer. HER2-low-positive breast cancer is a recently described subtype. We aimed to explore the clinical and molecular characteristics of gastric cancer with low HER2 expression, drawing on recent developments in breast cancer subtypes. MATERIALS AND METHODS: This retrospective study involved 129 patients with HER2-non-amplified gastric cancer treated in Iwate prefectural Iwai Hospital from 2013 to 2019. Tumors were classified as HER2-null or low-positive based on immunohistochemistry score 0 or 1 + or 2 + with HER2 negativity in situ hybridization, respectively. Statistical analyses, including Kaplan-Meier analyses and Cox proportional hazards model were conducted. RESULTS: Low HER2 expression was present in 26% (33/129) of the patients. Clinicopathological characteristics were not significantly different between the HER2-low and null groups. Kaplan-Meier analysis of overall survival was significantly longer in the HER2-low group than in the HER2-null group (P = 0.01). In multivariate Cox regression analysis, HER2-null status was associated with worse survival (hazard ratio 3.01; 95% confidence interval 1.18-7.65; and P = 0.02). CONCLUSION: This study highlights the prognostic importance of low HER2 expression in gastric cancer, similar to that observed in HER2-low-positive breast cancer, and suggests reclassification of gastric cancer to improve personalized treatment. Future studies should elucidate the molecular underpinnings of low HER2 expression in gastric cancer to guide novel therapeutic strategies and improve outcomes.

Time to symptom onset and manual reduction outcomes as predictors of bowel viability in incarcerated obturator hernias.

The current study aimed to identify the indications for manual reduction in incarcerated obturator hernias (OH). Further, whether time to symptom onset and manual reduction outcomes can be predictors of bowel viability and the need for bowel resection in incarcerated OH were examined. This retrospective study included 26 patients with incarcerated OH who underwent surgery. All patients underwent manual reduction, and computed tomography scan after manual reduction confirmed hernia release. Multivariate analyses were performed to determine the predictors of bowel resection. The bowel resection group had a significantly longer average time to symptom onset than the nonbowel resection group (88 vs 36 h). Further, the bowel resection group was more likely to have failed manual reduction than the nonbowel resection group. A time to symptom onset of ≥ 72 h and failed manual reduction were significant predictors of bowel viability. Age, sex, hernia localization, American Society of Anesthesiologists physical status score, and laboratory findings did not differ significantly between the bowel resection and nonbowel resection groups. Time to symptom onset and manual reduction outcomes are significant predictors of bowel viability in incarcerated OH. Patients with a time to symptom onset of ≥ 72 h and failed manual reduction require surgical evaluation due to a high risk of bowel nonviability. Therefore, a cautious approach is required in the management of OH, and further research on optimized treatment protocols should be conducted.

Manual reduction for incarcerated obturator hernia.

Emergent surgery is a common approach for incarcerated obturator hernias, with high morbidity and mortality rates. Moreover, there have been reports of elective surgery cases after noninvasive manual reduction. For a decade, the initial approach in our institution is also manual reduction unless bowel viability is poor. This study aimed to clarify the efficacy and safety of manual reduction followed by elective surgery. We retrospectively reviewed 50 cases of incarcerated obturator hernia from 2010 to 2022 at Iwate Prefectural Iwai Hospital. Manual reduction was attempted in 31 (62%) patients. The reduction was successful in 21 (42%) patients, and most of them received mesh repair using the extraperitoneal approach as elective surgery. However, two patients underwent emergent surgery in the waiting period because of late-onset constriction and a small bowel perforation. Patients with irreducible hernia underwent emergent surgery, except for two patients who received the best supportive care. Postoperative complications were observed in 5% and 22% of reducible and irreducible cases, respectively. Postoperative mortality was zero in both groups. Manual reduction is useful in some cases, but careful observation is needed because late-onset constriction and perforation could occur.

Heme-dependent recognition of 5-aminolevulinate synthase by the human mitochondrial molecular chaperone ClpX.

The caseinolytic mitochondrial matrix peptidase chaperone subunit (ClpX) plays an important role in the heme-dependent regulation of 5-aminolevulinate synthase (ALAS1), a key enzyme in heme biosynthesis. However, the mechanisms underlying the role of ClpX in this process remain unclear. In this in vitro study, we confirmed the direct binding between ALAS1 and ClpX in a heme-dependent manner. The substitution of C108 P109 [CP motif 3 (CP3)] with A108 A109 in ALAS1 resulted in a loss of ability to bind ClpX. Computational disorder analyses revealed that CP3 was located in a potential intrinsically disordered protein region (IDPR). Thus, we propose that conditional disorder-to-order transitions in the IDPRs of ALAS1 may represent key mechanisms underlying the heme-dependent recognition of ALAS1 by ClpX.