Background: The tumor microenvironment (TME) is an important factor that regulates the progression of colorectal cancer (CRC). Cancer-associated fibroblasts (CAFs) are the main mesenchymal cells in the TME and play a vital role in tumor progression; however, the specific underlying mechanisms require further study. Methods: Multiple single-cell and transcriptome data were analyzed and validated. Primary CAFs isolation, CCK8 assay, co-culture assay, western blotting, multiple immunofluorescence, qRT-PCR, ELISA, immunoprecipitation, ChIP, double luciferase, and animal experiments were used to explore the potential mechanism of MYL9 regulation in CRC. Results: Our findings revealed that MYL9 was predominantly localized and expressed in CAFs rather than in CRC cells, and bioinformatics analysis revealed that high MYL9 expression was strongly associated with poor overall and disease-free survival in various tumors. In addition, high MYL9 expression is closely associated with M2 macrophage infiltration, which can lead to an immunosuppressive microenvironment in CRC, making it insensitive to immunotherapy. Mechanically, MYL9 can regulate the secretion of CAFs on CCL2 and TGF-β1, thus affecting the immune microenvironment and progression of CRC. In addition, MYL9 bounded with IQGAP1 to regulate CCL2 and TGF-β1 secretion through the ERK 1/2 pathway, and CCL2 and TGF-β1 synergistically promoted CRC cells progression through the PI3K-AKT pathway. Furthermore, MYL9 promotes epithelial-mesenchymal transition (EMT) in CRC. During the upstream regulation of MYL9 in CAFs, we found that the EMT transcription factor ZEB1 could bind to the MYL9 promoter in CAFs, enhancing the activity and function of MYL9. Therefore, MYL9 is predominantly expressed in CAFs and can indirectly influence tumor biology and EMT by affecting CAFs protein expression in CRC. Conclusions: MYL9 regulates the secretion of cytokines and chemokines in CAFs, which can affect the immune microenvironment of CRC and promote CRC progression. The relationship between MYL9 expression and CRC clinical staging and immunotherapy is closer in CAFs than in tumor cells; therefore, studies using CAFs as a model deserve more attention when exploring tumor molecular targets in clinical research.

The relationship between systemic inflammation and tumor-associated bacteria is largely unknown in colorectal cancer (CRC). The primary aim of this study was to investigate the prognostic effects of the systemic inflammation response index (SIRI) on the survival outcomes of CRC patients who experienced surgical therapy, and the second aim was to reveal the potential association between SIRI levels and tumor-associated bacteria in CRC. We recruited a cohort of 298 CRC patients who experienced surgical resection in Wuhan Union Hospital. These patients were assigned to the low and high groups based on the cut-off value of SIRI. We utilized 1:1 propensity score matching (PSM) to reduce the potential confounding factors between the low SIRI group (N = 83) and the high SIRI group (N = 83). The total DNA of 166 paraffin-embedded tumor tissues and 24 frozen tumor tissues was extracted and amplified, and 16 S rRNA sequencing was employed to uncover the composition of microbiota between low and high SIRI groups. Survival analysis uncovered that the high SIRI cohort exhibited significantly shorter overall and disease-free survival time than low SIRI companions after PSM. The ROC analyses showed that the prediction abilities of SIRI were much higher than other serum inflammatory biomarkers for survival outcomes. The microbial richness and diversity in the low SIRI group were remarkably higher than those in the high SIRI group. At the phylum level, we found that Proteobacteria, Synergistetes, WPS-2, Thermil, Fusobacteria were enriched in the high SIRI group. Cupriavidus, Thermus, Ochrobactrum, Cupriavidus, Acidovorax were enriched in the high SIRI group at the genus level. 16 S rRNA based on frozen samples also obtained similar results. SIRI is a promising and novel prognostic biomarker among CRC sufferers who underwent surgical removal. There existed significant differences in the diversity and compositions of tumor-associated bacteria between the low and high SIRI groups.

Background: The body composition of patients with rectal cancer potentially affects postoperative outcomes. This study explored the correlations between skeletal muscle and adipose tissue quantified by computed tomography (CT) with postoperative complications and long‐term prognosis in patients with rectal cancer after surgical resection.Methods: This retrospective cohort study included patients with rectal cancer who underwent surgical resection at the Wuhan Union Hospital between 2014 and 2018. CT images within 3 months prior to the surgery were used to quantify the indices of skeletal muscle and adipose tissue at the levels of the third lumbar vertebra (L3) and umbilicus. Optimal cut‐off values for each index were defined separately for males and females. Associations between body composition and postoperative complications, overall survival (OS), and disease‐free survival (DFS) were evaluated using logistic and Cox proportional hazards models.Results: We included 415 patients (240 males and 175 females; mean age: 57.8 ± 10.5 years). At the L3 level, a high skeletal muscle density (SMD; hazard ratio [HR]: 0.357, 95% confidence interval [CI]: 0.191–0.665, P = 0.001; HR: 0.571, 95% CI: 0.329–0.993, P = 0.047) and a high skeletal muscle index (SMI; HR: 0.435, 95% CI 0.254–0.747, P = 0.003; HR: 0.568, 95% CI: 0.359–0.897, P = 0.015) were independent prognostic factors for better OS and DFS. At the umbilical level, a large intermuscular fat area (IMFA; HR: 1.904, 95% CI: 1.068–3.395, P = 0.029; HR: 2.064, 95% CI: 1.299–3.280, P = 0.002) was an independent predictive factor for worse OS and DFS, and a high SMI (HR: 0.261, 95% CI: 0.132–0.517, P < 0.001; HR: 0.595, 95% CI: 0.387–0.913, P = 0.018) was an independent prognostic factor for better OS and DFS. The models combining body composition and clinical indicators had good predictive abilities for OS. The receiver operating characteristic areas under the curve were 0.848 and 0.860 at the L3 and umbilical levels, respectively (both P < 0.05).Conclusions: No correlations existed between CT‐quantified body composition parameters and postoperative complications. However, a high SMD and high SMI were significantly associated with longer OS and DFS at the L3 level, whereas a large IMFA and low SMI were associated with worse OS and DFS at the umbilical level. Combining CT‐quantified body composition and clinical indicators could help physicians predict the prognosis of patients with rectal cancer after surgery.

Background: Tumour perineural invasion (PNI) is a predictor of poor prognosis, but its effect on the prognosis of patients with colorectal cancer (CRC) has not yet been elucidated. Methods: This retrospective study used propensity score matching (PSM). The clinical case data of 1470 patients with surgically treated stage I–IV CRC at Wuhan Union Hospital were collected. PSM was used to analyse and compare the clinicopathological characteristics, perioperative outcomes, and long-term prognostic outcomes of the PNI(+) and PNI(-) groups. The factors influencing prognosis were screened using Cox univariate and multivariate analyses. Results: After PSM, 548 patients were included in the study (n = 274 in each group). Multifactorial analysis showed that neurological invasion was an independent prognostic factor affecting patients’ OS and DFS (hazard ratio [HR], 1.881; 95% confidence interval [CI], 1.35–2.62; P = 0.0001; HR, 1.809; 95% CI, 1.353–2.419; P < 0.001). Compared to PNI(+) patients without chemotherapy, those who received chemotherapy had a significant improvement in OS (P < 0.01). The AUROC curve of OS in the PNI(+) subgroup (0.802) was higher than that after PSM (0.743), while that of DFS in the PNI(+) subgroup (0.746) was higher than that after PSM (0.706). The independent predictors of PNI(+) could better predict the prognosis and survival of patients with PNI(+). Conclusions: PNI significantly affects the long-term survival and prognosis of patients with CRC undergoing surgery and is an independent risk factor for OS and DFS in patients with CRC undergoing surgery. Postoperative chemotherapy significantly improved the OS of PNI(+) patients.

Obstructions can occur during any stage of colorectal cancer and correspond with poor prognosis. Obstructive colorectal cancer (OCRC) is harder and exhibits increased tumor budding and proliferation of myofibroblasts compared with nonobstructive colorectal cancer, suggesting that the occurrence of obstruction may be related to extracellular matrix (ECM) remodeling. In this study, we found that colorectal cancer and OCRC samples differed substantially in ECM composition, specifically in collagen (newly formed and mature) and proteoglycans (including glycosaminoglycan, hyaluronic acid, and chondroitin sulfate). OCRC also exhibited considerable changes in ECM biomechanics and collagen arrangement. Interestingly, OCRC samples presented a notable increase in matrix cancer-associated fibroblasts (mCAF). The abundance of mCAFs correlated with the accumulation of palmitic acid (PA), and high concentrations of PA increased the secretion of ECM-related proteins by mCAFs. Additionally, PA did not directly affect normal fibroblasts but rather activated the NF-κB pathway in tumor cells to stimulate secretion of CSF1, TGFβ1, and CXCL8, which promoted the activation of normal fibroblasts into mCAFs and exacerbated ECM stiffening. Drug screening with a natural compound library identified vanillylacetone as a potential inhibitor of PA-induced cytokine secretion and ECM stiffening. These findings highlight intratumoral PA accumulation as a key mechanism driving ECM alterations and OCRC progression and suggest that targeting this axis may be useful for treating patients with colorectal cancer with risk of obstruction. Significance: Palmitic acid accumulation activates the NF-κB pathway in colorectal cancer cells to promote cytokine secretion that facilitates the generation of matrix cancer-associated fibroblasts, driving extracellular matrix remodeling and development of obstructions.

Purpose: In the treatment of early-stage rectal cancer, a growing number of studies have shown that transanal endoscopic microsurgery is one of the alternatives to radical surgery adhering to total mesorectal excision that can reduce the incidence of adverse events without compromising treatment outcomes. The purpose of this meta-analysis is to compare the safety and treatment effect of transanal endoscopic microsurgery and radical surgery adhering to total mesorectal excision to provide a basis for clinical treatment selections. Method: We searched the literatures of four major databases, PubMed, Embase, Web of science, and Cochrane Library, without limitation of time. The literatures included randomized controlled studies and cohort studies comparing two surgical procedures of transanal endoscopic microsurgery and radical surgery adhering to total mesorectal excision. Treatment effectiveness and safety results of transanal endoscopic microsurgery and radical surgery were extracted from the included literatures and statistically analyzed using RevMan5.4 and stata17. Result: Ultimately, 13 papers were included in the study including 5 randomized controlled studies and 8 cohort studies. The results of the meta-analysis showed that the treatment effect and safety of both transanal endoscopic microsurgery and radical surgery in distant metastasis (RR, 0.59 (0.34, 1.02), P > 0.05), overall recurrence (RR, 1.49 (0.96, 2.31), P > 0.05), disease-specific-survival (RR, 0.74 (0.09, 1.57), P > 0.05), dehiscence of the sutureline or anastomosis leakage (RR, 0.57 (0.30, 1.06), P > 0.05), postoperative bleeding (RR, 0.47 (0.22, 0.99), P > 0.05), and pneumonia (RR, 0.37, (0.10, 1.40), P > 0.05) were not significantly different. However, they differ significantly in perioperative mortality (RR, 0.26 (0.07, 0.93, P < 0.05)), local recurrence (RR, 2.51 (1.53, 4.21), P < 0.05),_overall survival_ (RR, 0.88 (0.74, 1.00), P < 0.05), disease-free-survival (RR, 1.08 (0.97, 1.19), P < 0.05), temporary stoma (RR, 0.05 (0.01, 0.20), P < 0.05), permanent stoma (RR, 0.16 (0.08, 0.33), P < 0.05), postoperative complications (RR, 0.35 (0.21, 0.59), P < 0.05), rectal pain (RR, 1.47 (1.11, 1.95), P < 0.05), operation time (RR, −97.14 (−115.81, −78.47), P < 0.05), blood loss (RR, −315.52 (−472.47, −158.57), P < 0.05), and time of hospitalization (RR, −8.82 (−10.38, −7.26), P < 0.05). Conclusion: Transanal endoscopic microsurgery seems to be one of the alternatives to radical surgery for early-stage rectal cancer, but more high-quality clinical studies are needed to provide a reliable basis.