Emerging evidence of immunotherapy for colorectal cancer

Age-associated reduction of sinus macrophages in human mesenteric lymph nodes

There are numerous macrophages and dendritic cells in lymph nodes (LNs). Recent studies have highlighted that sinus macrophages (SMs) in LNs possess antigen-presenting capabilities and are related to anti-cancer immune responses. In this study, we assessed the distribution of SMs in mesenteric LNs removed during surgery for colorectal cancer. A marked reduction of SMs was noted in elderly patients, particularly those over 80 years old. We observed a disappearance of CD169-positive cells in LNs where SMs were reduced. In silico analysis of publicly available single-cell RNA sequencing data from LNs revealed that CD169-positive macrophages express numerous genes associated with antigen presentation and lymphocyte proliferation, similar to dendritic cells' functions. In conclusion, our study demonstrates that SMs, potentially crucial for immune activation, diminish in the LNs of elderly patients. This reduction of SMs may contribute to the immune dysfunction observed in the elderly.

Recent updates in the therapeutic uses of Pembrolizumab: a brief narrative review

INTRODUCTION

Treatment of cancer has been improved with the discovery of biological drugs that act as immune checkpoint inhibitors. In 2017, FDA designated pembrolizumab, an immune checkpoint inhibitor employed in immunotherapy, as the first tissue-agnostic cancer treatment.

OBJECTIVES

To review pembrolizumab's use in oncology, gather and examine the latest discoveries regarding the effectiveness of pembrolizumab in cancer treatment.

METHODOLOGY

A literature review was conducted through PubMed(Medline) from January 2015 to December 2023 using "pembrolizumab", "cancer" and "treatment" as search terms.

RESULTS

Pembrolizumab demonstrated effectiveness as primary treatment for metastatic nonsmall cell lung cancer, unresectable esophageal cancer, head and neck squamous cell carcinoma and alternative treatment for notable triple-negative breast cancer, biliary, colorectal, endometrial, renal cell, cervical carcinoma, and high microsatellite instability or mismatch repair deficiencies tumors. Pediatric applications include treatment for refractory Hodgkin lymphoma.

CONCLUSION

Evolving research on pembrolizumab allows a deeper clinical understanding, despite challenges as variable patient responses. Pembrolizumab has emerged as a pivotal breakthrough in cancer treatment, improving patient outcomes and safety.

Prognostic value of a modified‑immune scoring system in patients with pathological T4 colorectal cancer

Tumor-infiltrating immune cells, such as lymphocytes and macrophages, have been associated with tumor aggressiveness, prognosis and treatment response in colorectal cancer (CRC). An immune scoring system, Immunoscore (IS), based on tumor-infiltrating T cells in stage I-III CRC, was used to predict prognosis. An alternative immune scoring signature of immune activation (SIA) reflects the balance between anti- and pro-tumoral immune components. The present study aimed to evaluate the prognostic value of modified IS (mIS) and modified SIA (mSIA) in locally advanced pathological T4 (pT4) CRC, including stage IV CRC. Immunohistochemical staining for immune cell markers, such as CD3 (pan-T cell marker), CD8 (anti-tumoral cytotoxic T cell marker) and CD163 (tumor-supportive macrophage marker), in specimens from patients with radically resected pT4 CRC at stages II-IV was performed. mIS levels in the T4 CRC cohort were not associated with prognosis. However, low mSIA levels were associated with low survival. Furthermore, low mSIA was an independent predictor of recurrence in patients with radically resected pT4 CRC. In patients with CRC who did not receive postoperative adjuvant chemotherapy, low mSIA was a major poor prognostic factor; however, this was not observed in patients receiving adjuvant chemotherapy. Evaluation of the tumor-infiltrating immune cell population could serve as a valuable marker of recurrence and poor prognosis in patients with locally advanced CRC. mSIA assessment after radical CRC resection may be promising for identifying high-risk patients with pT4 CRC who require aggressive adjuvant chemotherapy.

Assessment of the DNA Mismatch Repair System Is Crucial in Colorectal Cancers Necessitating Adjuvant Treatment: A Propensity Score-Matched and Win Ratio Analysis

A deficient DNA mismatch repair (MMR) system is identified in a non-negligible part of sporadic colorectal cancers (CRCs), and its prognostic value remains controversial. High tumor mutational burden, along with a poor response to conventional chemotherapy and excellent results from immunotherapy, are the main features of this subset. The aim of this study was to evaluate the predictive value of DNA MMR system status for its best treatment. Four hundred and three CRC patients, operated on from 2014 to 2021 and not treated with immunotherapy, entered this study. Immunohistochemistry and polymerase chain reaction, as appropriate, were used to unequivocally group specimens into microsatellite stable (MSS) and instable (MSI) tumors. The win-ratio approach was utilized to compare composite outcomes. MSI tumors accounted for 12.9% of all series. The right tumor location represented the most important factor related to MSI. The status of the DNA MMR system did not appear to correlate with outcome in early-stage CRCs not requiring adjuvant treatment; in advanced stages undergoing conventional chemotherapy, MSI tumors showed significantly poorer overall and disease-free survival rates and the highest win ratio instead. The determination of DNA MMR status is crucial to recommending correct management. There is clear evidence that instable CRCs needing adjuvant therapy should undergo appropriate treatments.