Background: Microsatellite stable (MSS) colorectal cancer (CRC) has been referred to as the “cold tumor” because of almost no response to anti–programmed death-1 (PD-1) antibody. A recent REGONIVO trial showed that regorafenib plus nivolumab had an encouraging efficacy in MSS metastatic CRC (mCRC). However, only a small subset of patients may benefit from the combination therapy. We aim to evaluate the efficacy and safety data of immune checkpoint inhibitors combined with regorafenib in refractory MSS mCRC and to discover biomarkers that can effectively stratify the beneficial patient population.Methods: We retrospectively analyzed patients with MSS mCRC who received regorafenib combined with anti–PD-1 antibody therapy. The objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), overall survival (OS), and status of gene mutation were reviewed and evaluated.Results: Twenty-one patients received combination treatment. At a median treatment duration of 4 months, one patient achieved complete response, three patients achieved partial response, and two patients achieved stable disease as the best response. The ORR and DCR were 19% and 28.5% in the overall population, respectively. The median PFS was 4 months, and the median OS was 25 months. Only erbb2 receptor tyrosine kinase 2/erbb3 receptor tyrosine kinase 3 (ERBB2/ERBB3) mutation status was confirmed to be a potential predictive factor for effective treatment. In patients with ERBB2/ERBB3 mutation, ORR, DCR, and PFS exhibited significant improvements in comparison with that in wild-type patients. Grade 3 or higher treatment-related adverse events occurred in three patients (14.3%).Conclusions: Regorafenib in combination with PD-1 inhibitor provides a feasible treatment regimen for refractory MSS mCRC with tolerated toxicity. Patients with ERBB2/ERBB3 mutation may be the preferred population for this combination regimen.

Introduction: Stage I–III colorectal cancer patients are under risk of tumor recurrence and metachronous metastasis after radical surgery. An increased expression of transcription factor TEAD4 is associated with epithelial-mesenchymal transition, metastasis and poor prognosis in colorectal cancer. However, the mechanistic role of TEAD4 in driving colon cancer progression and its prognostic value in early stage of CRC remains unclear. Methods: In this study, the regulation, function and prognostic significance of TEAD4 and its new direct target gene SIX1 in CRC progression were evaluated using human tissues, molecular and cell biology. Results: We show that TEAD4 directly upregulates the expression of SIX1 at transcriptional level in CRC cells, establishing that SIX1 is a new direct target gene of TEAD4. TEAD4 promotes EMT and cell migration of CRC cells, while SIX1 knockdown attenuates this effect and SIX1 overexpression enhances this effect, indicating that SIX1 mediates the function of TEAD4 in promoting cell migration in CRC cells. Clinically, nuclear TEAD4, overexpression of SIX1 and nuclear TEAD4 with SIX1 overexpression predict poor prognosis in CRC patients. Discussion: Our study identifies TEAD4-SIX1-CDH1 form a novel signaling axis, which contributes to CRC progression, and its aberrant expression and activation predicts poor prognostic for CRC patients in stage I–III.

Background: Microsatellite instability-high (MSI-H) tumors, with elevated tumor mutational burden and expression of neoantigens, represent a distinct immune-activated subpopulation in colorectal cancer (CRC), characterized by strong lymph node reaction, locally advanced tumor and higher total lymph nodes harvested (TLN), but less metastatic lymph nodes and fewer incidence of III-IV stage. Host immune response to tumor and lymph nodes may be an important prognostic factor. However, N stage and LNR (Lymph-Node Ratio) have limitations in predicting the prognosis of MSI-H patients. Negative lymph node count (NLC) provided a more precise representation of immune activation status and extent of tumor metastasis. The study aims to detect prognostic significance of NLC in MSI-H CRC patients, and compare it with N stage, TLN and LNR. Methods: Retrospective data of 190 consecutive MSI-H CRC patients who received curative resection were collected. Survival analyses were performed using the Kaplan–Meier method. Clinicopathological variables including NLC, N stage, TLN and LNR were studied in univariate and multivariate COX regression analyses. ROC (receiver operating characteristic curve) and concordance index were employed to compare the differences in predictive efficacy between NLC, N stage, TLN and LNR. Results: Patients with increased NLC experienced a significantly improved 5-years DFS and OS in Kaplan–Meier analysis, univariate analysis, and multivariate analysis, independent of potential confounders examined. Increased NLC corresponded to elevated 5-years DFS rate and 5-years OS rate. AUC (area under curve) and concordance index of NLC in DFS and OS predicting were both significantly higher than N stage, TLN and LNR. Conclusions: Negative lymph node is an important independent prognostic factor for MSI-H patients. Reduced NLC is associated with tumor recurrence and poor survival, which is a stronger prognostic factor than N stage, TLN and LNR.

With the emergence of novel variants, there have been widespread COVID-19 infections in the Chinese mainland recently. Compared to ancestral COVID-19 variants, Omicron variants become more infectious, but less virulent. Previous studies have recommended postponing non-emergency surgery for at least 4–8 weeks after COVID-19 infection. However, delayed surgery has been shown to be associated with tumor progression and worse overall survival for cancer patients. Here, we examined surgery risk and optimal timing for colorectal cancer patients with perioperative COVID-19 infection. A total of 211 patients who underwent colorectal cancer surgery from 1 October 2022 to 20 January 2023 at Xinhua Hospital were included. In addition, COVID-19-infected patients were further categorized into three groups based on infected time (early post-COVID-19 group, late post-COVID-19 group and postoperative COVID-19 group). The complication rate in patients with COVID-19 infection was 26.3%, which was significantly higher than in control patients (8.4%). The most common complications in COVID-19-infected patients were pneumonia, ileus and sepsis. Patients who underwent surgery close to the time of infection had increased surgery risks, whereas surgery performed over 1 week after recovery from COVID-19 did not increase the risk of postoperative complications. In conclusion, surgery performed during or near the time of COVID-19 infection is associated with an increased risk of developing postoperative complications. We recommend that the safe period for patients with recent COVID-19 infection in colorectal cancer surgery be at least 1 week after recovery from COVID-19.