Transcriptomic Analyses of Pretreatment Tumor Biopsy Samples, Response to Neoadjuvant Chemoradiotherapy, and Survival in Patients With Advanced Rectal Cancer

Negative prognostic impact of Co-mutations in TGFβ and TP53 pathways in surgically resected rectal tumors following neoadjuvant chemoradiotherapy

BACKGROUND

Preoperative neoadjuvant chemoradiotherapy (nCRT) followed by total mesorectal excision (TME) is a common approach for treating patients with locally advanced rectal cancer. Nevertheless, the mutational profile and its prognostic impact in surgically resected tumor specimens after nCRT remains to be clarified.

METHODS

The comprehensive analysis of mutational landscape was retrospectively conducted by target regions sequencing approach that covered 150 tumor-related genes. Univariate and multivariate logistic regression and Cox regression was used to examine the association of mutation status in genes and pathways with pathological response and prognosis. Data from Memorial Sloan Kettering Cancer Center (MSK) cohort was used for comparison with our results.

RESULTS

The top five commonly mutated genes in resected rectal tumor tissue samples following nCRT were TP53 (42%), APC (31%), KRAS (27%), PIK3CA (14%) and FBXW7 (11%). Mutations in the WNT pathway, which was mainly represented by APC mutation, were found to be significantly associated with tumor regression grade (TRG) 3. In our cohort, co-mutations in the receptor tyrosine kinase (RTK)/RAS and WNT pathways were found to be independently associated with reduced risk of recurrent and significantly associated with longer disease-free survival (DFS). In both our cohort and the MSK cohort, co-mutations in the TGF-β and TP53 pathways were significantly associated with worse DFS.

CONCLUSIONS

Resected rectal tumor samples from patients without complete pathological response can be appropriately used to detect mutations. Co-mutations in the TGF-β and TP53 pathways may provide more prognostic information beyond commonly used clinical factors.

Tertiary lymphoid structures predict survival and response to neoadjuvant therapy in locally advanced rectal cancer

Tertiary lymphoid structure (TLS) contributes to the anti-tumor immune response, and predicts the prognosis of colorectal cancer patients. However, the potential impact of TLS in shaping the immune status of rectal adenocarcinoma, and the intrinsic relationship between TLS and neoadjuvant therapies (neoTx) remain unclear. We performed hematoxylin-eosin staining, immunohistochemical and biomolecular analyses to investigate TLS and tumor-infiltrating lymphocytes (TILs) in 221 neoTx-treated and 242 treatment-naïve locally advanced rectal cancer (LARC) patients. High TLS density was significantly associated with the absence of vascular invasion, a lower neutrophil-to-lymphocyte ratio, increased TLS maturity, a longer recurrence-free survival (RFS) (hazard ratio [HR] 0.2985 95% confidence interval [CI] 0.1894-0.4706, p < 0.0001) and enhanced infiltration of adaptive immune cells. Biomolecular analysis showed that high TLS-score was strongly associated with more infiltration of immune cells and increased activation of immune-related pathways. TLS+ tumors in pre-treatment specimens were associated with a higher proportion of good respond (62.5% vs. 29.8%, p < 0.0002) and pathological complete remission (pCR) (40.0% vs. 11.1%, p < 0.0001), and significantly increased RFS (HR 0.3574 95%CI 0.1489-0.8578 p = 0.0213) compared with TLS- tumors in the neoTx cohort, which was confirmed in GSE119409 and GSE150082. Further studies showed that neoTx significantly reduced TLS density and maturity, and abolished the prognostic value of TLS. Our study illustrates that TLS may have a key role in mediating the T-cell-inflamed tumor microenvironment, which also provides a new direction for neoTx, especially neoadjuvant immunotherapy, in LRAC patients.

STAT3-Mediated Ferroptosis is Involved in Sepsis-Associated Acute Respiratory Distress Syndrome

Sepsis-induced acute respiratory distress syndrome (ARDS) poses a grave danger to life, resulting from sepsis-induced multi-organ failure. Although ferroptosis, a form of iron-dependent lipid peroxidative cell death, has been associated with sepsis-induced ARDS, the specific mechanisms are not fully understood. In this study, we utilized WGCNA, PPI, friends analysis, and six machine learning techniques (Lasso, SVM, RFB, XGBoost, AdaBoost, and LightGBM) to pinpoint STAT3 as a potential diagnostic marker. A significant increase in monocyte and neutrophil levels was observed in patients with sepsis-induced ARDS, as revealed by immune infiltration analyses, when compared to controls. Moreover, there was a positive correlation between STAT3 expression and the level of infiltration. Single-cell analysis uncovered a notable disparity in B-cell expression between sepsis and sepsis-induced ARDS. Furthermore, in vitro experiments using LPS-treated human bronchial epithelial cells (BEAS-2B) and THP1 cells demonstrated a significant increase in STAT3 phosphorylation expression. Additionally, the inhibition of STAT3 phosphorylation by Stattic effectively prevented LPS-induced ferroptosis in both BEAS-2B and THP1 cells. This indicates that the activation of STAT3 phosphorylation promotes ferroptosis in human bronchial epithelial cells in response to LPS. In summary, this research has discovered and confirmed STAT3 as a potential biomarker for the diagnosis and treatment of sepsis-induced ARDS.

Intratumoral Budding and CD8-Positive T-cell Density in Pretreatment Biopsies as a Predictor of Response to Neoadjuvant Chemoradiotherapy in Advanced Rectal Cancer

BACKGROUND

Neoadjuvant chemoradiotherapy (CRT) is the standard treatment for advanced rectal cancer. Yet, the response to CRT varies from complete response to zero tumor regression.

MATERIALS AND METHODS

The impact of intratumoral budding (ITB) and intratumoral CD8+ cell density on response to CRT and survival were evaluated in biopsy samples from 266 patients with advanced rectal cancer who were treated with long-course neoadjuvant CRT. The expression of epithelial-mesenchymal transition (EMT) markers was compared between patients with high and low ITB, using data from 174 patients with RNA sequencing.

RESULTS

High ITB was observed in 62 patients (23.3%). There was no association between ITB and CD8+ cell density. The multivariable logistic regression analysis showed that high CD8+ cell density (OR, 2.69; 95% CI, 1.45-4.98; P = .002) was associated with good response to CRT, whereas high ITB (OR, 0.33; 95% CI, 0.14-0.80; P = .014) was associated with poor response. Multivariable Cox regression analysis for survival showed that high CD8+ cell density was associated with better recurrence-free survival (HR, 0.41; 95% CI, 0.24-0.72; P = .002) and overall survival (HR, 0.36; 95% CI, 0.17-0.74; P = .005), but significance values for ITB were marginal (P = .104 for recurrence-free survival and P = .163 for overall survival). The expression of EMT-related genes was not significantly different between patients with high and low ITB.

CONCLUSION

ITB and CD8+ cell density in biopsy samples may serve as useful biomarkers to predict therapy response in patients with rectal cancer treated with neoadjuvant CRT.

Multiphase and multiparameter MRI-based radiomics for prediction of tumor response to neoadjuvant therapy in locally advanced rectal cancer

BACKGROUND

To develop and validate radiomics models for prediction of tumor response to neoadjuvant therapy (NAT) in patients with locally advanced rectal cancer (LARC) using both pre-NAT and post-NAT multiparameter magnetic resonance imaging (mpMRI).

METHODS

In this multicenter study, a total of 563 patients were included from two independent centers. 453 patients from center 1 were split into training and testing cohorts, the remaining 110 from center 2 served as an external validation cohort. Pre-NAT and post-NAT mpMRI was collected for feature extraction. The radiomics models were constructed using machine learning from a training cohort. The accuracy of the models was verified in a testing cohort and an independent external validation cohort. Model performance was evaluated using area under the curve (AUC), sensitivity, specificity, positive predictive value, and negative predictive value.

RESULTS

The model constructed with pre-NAT mpMRI had favorable accuracy for prediction of non-response to NAT in the training cohort (AUC = 0.84), testing cohort (AUC = 0.81), and external validation cohort (AUC = 0.79). The model constructed with both pre-NAT and post-NAT mpMRI had powerful diagnostic value for pathologic complete response in the training cohort (AUC = 0.86), testing cohort (AUC = 0.87), and external validation cohort (AUC = 0.87).

CONCLUSIONS

Models constructed with multiphase and multiparameter MRI were able to predict tumor response to NAT with high accuracy and robustness, which may assist in individualized management of LARC.

Establishment of a novel indicator of pyroptosis regulated gene transcription level and its application in pan-cancer

Pyroptosis is a type of programmed cell death and plays a dual role in distinct cancers. It is elusive to evaluate the activation level of pyroptosis and to appraise the involvement of pyroptosis in the occurrence and development of diverse tumors. Accordingly, we herein established an indicator to evaluate pyroptosis related gene transcription levels based on the expression level of genes involved in pyroptosis and tried to elaborated on the association between pyroptosis and tumors across diverse tumor types. We found that pyroptosis related gene transcription levels could predict the prognosis of patients, which could act as either a favorable or a dreadful factor in diverse cancers. According to signaling pathway analyses we observed that pyroptosis played a significant role in immune regulation and tumorigenesis and had strong links with other forms of cell death. We also performed analysis on the crosstalk between pyroptosis and immune status and further investigated the predictive potential of pyroptosis level for the efficacy of immunotherapy. Lastly, we manifested that pyroptosis status could serve as a biomarker to the efficacy of chemotherapy across various cancers. In summary, this study established a quantitative indicator to evaluate pyroptosis related gene transcription levels, systematically explored the role of pyroptosis in pan-cancer. These results could provide potential research directions targeting pyroptosis, and highlighted that pyroptosis may be used to develop a novel strategy for the treatment of cancer.