Ying Song

Rac1 in gastric cancer: a molecular driver of invasion, EMT, and therapeutic resistance

Abstract Gastric cancer (GC) ranks as the fifth most common cancer worldwide and is the third main cause of cancer-related mortality, posing a substantial burden to global public health. Research suggests that targeted therapy and immunotherapy may become more effective treatment options for advanced, unresectable, or metastatic gastric cancer. Ras-related C3 botulinum toxin substrate 1 (Rac1), a small GTP-binding protein within the Rac subfamily of the Rho GTPase family, is a critical molecule that promotes cancer cell invasion and metastasis by regulating signal transmission and promoting cell polarity. It has emerged as a key driver of tumor development and metastasis in several malignancies, including breast, lung, prostate, ovarian, gastric, and pancreatic cancers. This review summarizes the structure, regulatory dynamics, and signaling mechanisms of Rac1 in gastric cancer growth, epithelial-to-mesenchymal transition (EMT), and metastasis, as well as the roles of factors such as hypoxia, oxidative stress, and H. pylori infection. Additionally, it highlights small-molecule inhibitors targeting Rac1, miRNAs capable of suppressing Rac1, and ongoing research on Rac1-related immunotherapy. The potential of Rac1 as a therapeutic biomarker in gastric cancer and the remaining challenges in this area are also discussed. This review advances the understanding of Rac1’s role in gastric cancer, provides a theoretical foundation for further studies, and supports the development of precision medicine for this disease.

Cost-effectiveness of pembrolizumab plus chemotherapy for advanced endometrial cancer

To assess the cost-effectiveness of pembrolizumab in combination with chemotherapy compared to chemotherapy alone, based on the results of the NRG-GY018 trial, in patients with advanced or recurrent endometrial cancer (EC), stratified by mismatch repair-deficient (dMMR) and mismatch repair-proficient (pMMR) subgroups. A Markov model was used to simulate patients receiving either pembrolizumab plus chemotherapy or chemotherapy alone. Lifetime costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratio (ICER) were calculated using a willingness-to-pay (WTP) threshold of $150,000/QALY. Univariate and probabilistic sensitivity analyses were conducted to assess the robustness of our findings. The addition of pembrolizumab to chemotherapy led to an incremental gain of 4.05 QALYs at an additional cost of $167,224, resulting in an ICER of $41,305.09/QALY compared to chemotherapy alone in dMMR EC. Additionally, there were 0.93 additional QALYs at an additional cost of $83,661, which resulted in an ICER of $90,284.80/QALY in pMMR EC. Sensitivity analyses indicated that the cost of pembrolizumab, utility of progressed disease, and utility of progression-free survival had the greatest impact on the results. Probabilistic sensitivity analysis showed that pembrolizumab was considered cost-effective at a 100% probability at a WTP threshold of $150,000 per QALY. Pembrolizumab, when combined with chemotherapy, was found to be cost-effective compared to chemotherapy alone both for patients with advanced or recurrent dMMR and pMMR EC from the perspective of a payer in the United States.

Cost-effectiveness of atezolizumab plus chemotherapy for advanced/recurrent endometrial cancer

This study assessed the cost-effectiveness of atezolizumab in combination with chemotherapy for patients with advanced or recurrent endometrial cancer (EC) from the U.S. payer's perspective. A cost-effectiveness study was conducted using a Markov model based on ENGOT-en7/MaNGO/AtTEnd clinical trials. The population consisted of patients with EC, stratified by mismatch repair-deficient (dMMR) and mismatch repair-proficient (pMMR) subgroups. The model simulated patients receiving either atezolizumab plus chemotherapy or chemotherapy alone. Cost, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratio (ICER) were calculated using a Willingness-to-Pay (WTP) threshold of $150,000/QALY. Sensitivity analyses were performed. Adding atezolizumab to chemotherapy in dMMR EC resulted in an incremental gain of 3.31 QALYs but at an additional cost of $855,042, leading to an ICER of $258,391.07/QALY compared to chemotherapy alone. In pMMR EC, there was a gain of 0.50 QALYs with an additional cost of $140,502, resulting in an ICER of $279,239.72/QALY. The overall ICER for EC was $216,459.34/QALY. Scenario analysis indicated that administering atezolizumab for a maximum of 2 years improved cost-effectiveness in dMMR EC, with an ICER of $70,695.96/QALY falling within the predetermined WTP threshold. For patients with advanced or recurrent EC, the combination of atezolizumab and chemotherapy may not prove cost-effective. However, administering atezolizumab for a limited period of maximum 2 years could improve cost-effectiveness in dMMR EC.