DNA mismatch repair status and colon cancer recurrence and survival in clinical trials of 5-fluorouracil-based adjuvant therapy

Streamlining the diagnostic pathway for Lynch syndrome in colorectal cancer patients: a 10-year experience in a single Italian Cancer Center

BACKGROUND

Universal screening of colorectal cancer (CRC) patients for Lynch syndrome (LS) through MisMatch Repair (MMR) testing is recommended. BRAF V600E mutation and/or MLH1 promoter methylation (Reflex Testing, RefT)generally rule out LS in MLH1-deficient (dMLH1) patients. We estimated the impact of RefTon genetic counseling (GC) and on the diagnostic yield of genetic testing (GT).

METHODS

Overall, 3199 CRC patients were referred to our center between 2011 and 2021. Patients referred until January 2019 (n=2536) underwent universal MMR testing and were termed 'Cohort A'; among patients after February 2019 (n=663), 'Cohort B', RefT was also performed in dMLH1 patients.

RESULTS

Overall, 401/3199 patients (12.5%) were MMR-deficient (dMMR); 312 (77.8%) in cohort A and 89 (22.2%) inB; 346/401 were dMLH1 (86.3%), 262/312 (83.9%) in cohort A and 84/89 (94.3%) in B. In Cohort A, 91/312 (29.1%) dMMR patients were referred to GC, 69/91 (75.8%) were in the dMLH1 group; 57/69 (82.6%) dMLH1 patients underwent GT and 1/57 (1.7%) had LS. In Cohort B, 3/84 dMLH1 patients did not undergo BRAF testing. Three BRAF wt and not hypermethylated of the remaining 81 dMLH1 patients were referred to GC and GT, and one had LS. This diagnostic pathway reduced GC referrals by 96% (78/81) in Cohort B and increased the diagnostic yield of GT by about 20 times.

CONCLUSION

Our findings support RefT in dMLH1 CRC patients within the LS diagnostic pathway, as it reduces the number of GC sessions needed and increases the diagnostic yield of GT.

Unraveling the Interplay of KRAS, NRAS, BRAF, and Micro-Satellite Instability in Non-Metastatic Colon Cancer: A Systematic Review

Microsatellite Instability (MSI-H) occurs in approximately 15% of non-metastatic colon cancers, influencing patient outcomes positively compared to microsatellite stable (MSS) cancers. This systematic review focuses on the prognostic significance of KRAS, NRAS, and BRAF mutations within MSI-H colon cancer. Through comprehensive searches in databases like MEDLINE, EMBASE, and others until 1 January 2024, we selected 8 pertinent studies from an initial pool of 1918. These studies, encompassing nine trials and five observational studies involving 13,273 patients, provided insights into disease-free survival (DFS), survival after recurrence, and overall survival. The pooled data suggest that while KRAS and BRAF mutations typically predict poorer outcomes in MSS colorectal cancer, their impact is less pronounced in MSI contexts, with implications varying across different stages of cancer and treatment responses. In particular, adverse effects of these mutations manifest significantly upon recurrence rather than affecting immediate DFS. Our findings confirm the complex interplay between genetic mutations and MSI status, emphasizing the nuanced role of MSI in modifying the prognostic implications of KRAS, NRAS, and BRAF mutations in colon cancer. This review underscores the importance of considering MSI alongside mutational status in the clinical decision-making process, aiming to tailor therapeutic strategies more effectively for colon cancer patients.

One-instrument, objective microsatellite instability analysis using high-resolution melt

In recent years, immune checkpoint inhibitors have proved immense clinical progression in the treatment of certain cancers. The efficacy of immune checkpoint inhibitors is correlated with mismatch repair system deficiency and is exceptionally administered based exclusively on this biological mechanism independent of the cancer type. The promising effect of immune checkpoint inhibitors has left an increasing demand for analytical tools evaluating the mismatch repair status. The analysis of microsatellite instability (MSI), reflecting an indirect but objective manner the inactivation of the mismatch repair system, plays several roles in clinical practice and, therefore, its evaluation is of high relevance. Analysis of MSI by PCR followed by fragment analysis on capillary electrophoresis remains the gold standard method for detection of a deficient mismatch repair system and thereby treatment with immune checkpoint inhibitors. Novel technologies have been applied and concepts such as tumor mutation burden have been introduced. However, to date, most of these technologies require high costs or the need of matched non-tumor tissue as internal comparator. In this study, we present a novel, one-instrument, fast, and objective method for the detection of MSI (MicroSight® MSI 1-step HRM Analysis), which does not depend on the use of matched non-tumor tissue. The assay analyzes five well-described mononucleotide microsatellite sequences by real-time PCR followed by high-resolution melt and evaluates microsatellite length variations via PCR product melting profiles. The assay was evaluated using two different patient cohorts and evaluation included several DNA extraction methodologies, two different PCR platforms, and an inter-laboratory ring study. The MicroSight® MSI assay showed a high repeatability regardless of DNA extraction method and PCR platform, and a 100% agreement of the MSI status with PCR fragment analysis methods applied as clinical comparator.

Sex Difference of Colon Adenoma Pathway and Colorectal Carcinogenesis

Colorectal cancer (CRC) is one of the most common causes of cancer morbidity in both sexes but shows sex differences. First, sex-specific differences in tumor recurrence and survival rates have been reported. For example, the development of CRC is found about 1.5 times higher and 4-8 years earlier in males compared to females, suggesting the protective role of estrogen in the disease. Furthermore, female patients have a higher risk of developing right-sided (proximal) colon cancer than male patients, which is known to have more aggressive clinical character compared to left-sided (distal) colon cancer. That is, left and right CRCs show differences in carcinogenic mechanism, that the chromosomal instability pathway is more common in left colon cancer while the microsatellite instability and serrated pathways are more common in right colon cancer. It is thought that there are sex-based differences on the background of carcinogenesis of CRC. Sex differences of CRC have two aspects, sexual dimorphism (biological differences in hormones and genes) and gender differences (non-biological differences in societal attitudes and behavior). Recently, sex difference of colon adenoma pathway and sexual dimorphism in the biology of gene and protein expression, and in endocrine cellular signaling in the CRC carcinogenesis have been accumulated. In addition, behavioral patterns can lead to differences in exposure to risk factors such as drinking or smoking, diet and physical activity. Therefore, understanding sex/gender-related biological and sociocultural differences in CRC risk will help in providing strategies for screening, treatment and prevention protocols to reduce the mortality and improve the quality of life. In this review, sex/gender differences in colon adenoma pathway and various aspects such as clinicopathological, biological, molecular, and socio-cultural aspects of CRC were described.

Unique characteristics of the tumor immune microenvironment in young patients with metastatic colorectal cancer

Introduction

Metastatic colorectal cancer (mCRC) remains a common and highly morbid disease, with a recent increase in incidence in patients younger than 50 years. There is an acute need to better understand differences in tumor biology, molecular characteristics, and other age-related differences in the tumor microenvironment (TME).

Methods

111 patients undergoing curative-intent resection of colorectal liver metastases were stratified by age into those <50 years or >65 years old, and tumors were subjected to multiplex fluorescent immunohistochemistry (mfIHC) to characterize immune infiltration and cellular engagement.

Results

There was no difference in infiltration or proportion of immune cells based upon age, but the younger cohort had a higher proportion of programmed death-ligand 1 (PD-L1)+ expressing antigen presenting cells (APCs) and demonstrated decreased intercellular distance and increased cellular engagement between tumor cells (TCs) and cytotoxic T lymphocytes (CTLs), and between TCs and APCs. These trends were independent of microsatellite instability in tumors.

Discussion

Age-related differences in PD-L1 expression and cellular engagement in the tumor microenvironment of patients with mCRC, findings which were unrelated to microsatellite status, suggest a more active immune microenvironment in younger patients that may offer an opportunity for therapeutic intervention with immune based therapy.

China special issue on gastrointestinal tumors-Regulatory-immunoscore-A novel indicator to guide precision adjuvant chemotherapy in colorectal cancer

Novel biomarkers are essential to improve the treatment efficacy and overall survival of stage II and III colorectal cancer (CRC), allowing for personalized treatment decisions. Here, the densities of CD8+ and FOXP3+ T cells in the tumor and invasive margin were processed by immunohistochemistry and digital pathology to form a scoring system named regulatory-Immunoscore (RIS). Cox proportional hazards regression models were used to determine the risk factors associated with time to recurrence. Harrell's concordance index and the time-dependent area under the curve were used to assess model performance. A total of 1213 stage I-III DNA mismatch repair-proficient colorectal cancer (pMMR CRC) patients were randomly assigned to a training set (n = 642) and a validation set (n = 571). From the Cox multivariable analysis, the association of RIS with survival was independent of patient age, sex and anatomy-based tumor risk parameters (P < .0001). For stage II patients, chemotherapy was significantly associated with better recurrence time in patients with low (95% confidence interval [CI]: 0.11-0.54, P = .001) and intermediate (95% CI = 0.25-0.57, P < .001) RIS values. In stage III patients treated with adjuvant chemotherapy, a treatment duration of 6 or more months was significantly associated with better recurrence time in patients with intermediate RIS values (95% CI = 0.38-0.90, P = .016) when compared with duration under 6 months. Therefore, these findings suggest that RIS is reliable for predicting recurrence risk and treatment responsiveness for patients with stage I-III pMMR CRC.

[Novel Treatment Concepts in Patients with Colorectal Carcinomas and High Microsatellite Instability]

Approximately 15% of patients with colorectal cancer show high microsatellite instability (MSI-high) in their tumour tissue. For one third of these patients, there is a hereditary cause for this finding - that leads to the diagnosis of Lynch Syndrome. In combination with clinical findings such as the Amsterdam or the revised Bethesda criteria, MSI-high status has been used as a tool in identifying patients at risk. Today, MSI-status has gained much more importance, due to its impact on treatment decisions. Patients with UICC II cancers should not receive adjuvant treatment. For patients with distant metastases and MSI-high status, immune checkpoint inhibitors can be given as first line therapy - with tremendous success. Novel data show a deep response for immune checkpoint antibodies in patients with locally advanced colon as well as rectal cancer in a neoadjuvant setting. Especially for patients with MSI-high rectal cancer, there might be a novel therapeutic regimen utilising immune checkpoint inhibitors without neoadjuvant radio-chemotherapy and even without surgery. This could lead to a relevant reduction in morbidity in this patient cohort. In conclusion, universal MSI-testing is essential for identifying patients at risk for Lynch syndrome and for optimal decision making in treatment planning.

Axillary cutaneous metastasis of colon cancer with microsatellite instability-high and BRAF V600E mutation treated with curative-intent surgery: a case report

BACKGROUND

Colorectal cancer (CRC) metastasizes to various organs, while cutaneous metastases are rare. Although there have been several previous reports of axillary cutaneous metastases with other metastases of CRC, there has never been a report of axillary cutaneous metastasis of CRC that could be treated with curative-intent surgery.

CASE PRESENTATION

A 68-year-old female was diagnosed with an axillary cutaneous tumor and ascending colon cancer with invasion to the duodenum. Histopathological and immunohistochemical analysis revealed that the axillary cutaneous tumor showed adenocarcinoma and the same expression pattern for cytokeratin 7, cytokeratin 20, and CDX2 as the ascending colon cancer, and that proved to be KRAS-NRAS wild type, MSI-H, and with a BRAF V600E mutation. The patient underwent a two-stage resection with curative intent after receiving neoadjuvant chemotherapy which consisted of one cycle of modified FOLFOX6 followed by two cycles of FOLFOXIRI. During and after the two operations, the patient received a total of nine cycles of modified FOLFOX6 as adjuvant chemotherapy. Two years after the initial surgery, and 1 year and 8 months after the second surgery, the patient is alive without recurrence.

CONCLUSIONS

To the best of our knowledge, this is the first report of axillary cutaneous metastasis of CRC with microsatellite instability-high and BRAF V600E mutation that could be treated with curative-intent surgery. It is important to recognize the presence of such cases for the accurate diagnosis and treatment of CRC with cutaneous metastasis.

Time to recurrence and its relation to survival after recurrence in patients resected for stage III colon cancer

BACKGROUND

It is intuitively thought that early relapse is associated with poor survival after recurrence (SAR) in resected colon cancer (CC) patients, but this has never been formally studied.

METHODS

We pooled data from stage III patients treated with oxaliplatin-based adjuvant therapy in two phase III trials, to analyse time to recurrence (TTR) and its relationship with SAR. TTR and SAR were also studied according to molecular status (mismatch repair (MMR), RAS, and BRAFV600E). Early relapsing patients were defined as patients having a TTR event within 12 months after starting adjuvant chemotherapy.

RESULTS

4548 stage III CC patients were included in the present analysis. Deficient MMR (dMMR) CC patients experienced fewer recurrences than proficient (p)MMR CC patients (18.8% versus 27.6%) but had a significantly shorter median TTR (mTTR; 0.74 versus 1.40 years, p < 0.0001). In pMMR patients, BRAF and RAS mutations were also associated with earlier mTTR as compared to double wild-type (WT) patients (0.99 versus 1.38 versus 1.54 years, respectively, p < 0.0001). Early recurrence occurred in 397 patients and was associated with a median SAR (2.2 versus 3.3 years, p = 0.0007). However, this association was mainly due to pMMR/RAS and BRAFV600E mutated tumours and was not confirmed in dMMR and pMMR/double WT subgroups.

CONCLUSION

In resected stage III CC treated with standard oxaliplatin-based adjuvant therapy, TTR varies between dMMR, pMMR/RAS, or BRAFV600E mutated and pMMR/double WT tumours. In addition, early relapse is associated with poor survival, mainly due to patients resected for a pMMR/RAS or BRAFV600E mutated tumour.

Second primary cancer among 217702 colorectal cancer survivors: An analysis of national German cancer registry data

With improvements in survival after colorectal cancer (CRC), more survivors are at risk of developing a second cancer, particularly in younger populations where CRC incidence is increasing. We estimated the incidence of second primary cancer (SPC) in CRC survivors and its potential risk factors. We identified CRC cases diagnosed between 1990 and 2011 and SPCs until 2013 from nine German cancer registries. Standardized incidence ratios (SIR) and absolute excess risk (AER) per 10 000 person-years were calculated and were stratified by index site: colon cancer (CC) and rectal cancer (RC), age and sex. Cox regression assessed potential SPC risk factors, including primary tumor-related therapy considering death as a competing risk. We included 217 202 primary CRC cases. SPC occurred in 18 751 CRC survivors (8.6%; median age: 69 years). Risk of cancer was significantly higher in CRC survivors than in the general population (SIR males 1.14, 95% confidence interval [CI] 1.12-1.17, AER = 24.7; SIR females 1.20, 95% CI 1.17-1.23, AER = 22.8). Increased risks of SPCs were observed for the digestive system, urinary system and female and male reproductive organs. CRC incidence increased in younger persons (<50 years) and SPC incidence was 4-fold in this group (SIR males 4.51, 95% CI 4.04-5.01, AER = 64.2; SIR females 4.03, 95% CI 3.62-4.48, AER = 77.0). Primary tumor-related factors associated with SPC risk were right-sided cancer and smaller primary tumor size. Treatment and risk of SPC differed for CC (no effect) and RC (lower risk after chemotherapy). CRC survivors have excess risk of developing SPC, with particular characteristics that could guide targeted surveillance.

Mouse Models of Metastasis and Dormancy

Metastasis is the ultimate and often lethal stage of cancer. Metastasis occurs in three phases that may vary across individuals: First, dissemination from the primary tumor. Second, tumor dormancy at the metastatic site where micrometastatic cancer cells remain quiescent or, in dynamic cycles of proliferation and elimination, remaining clinically undetectable. Finally, cancer cells are able to overcome microenvironmental constraints for outgrowth, or the formation of clinically detectable macrometastases that colonize distant organs and are largely incurable. A variety of approaches have been used to model metastasis to elucidate molecular mechanisms and identify putative therapeutic targets. In particular, metastatic dormancy has been challenging to model in vivo due to the sparse numbers of cancer cells in micrometastasis nodules and the long latency times required for tumor outgrowth. Here, we review state-of-the art genetically engineered mouse, syngeneic, and patient-derived xenograft approaches for modeling metastasis and dormancy. We describe the advantages and limitations of various metastasis models, novel findings enabled by such approaches, and highlight opportunities for future improvement.

The prognostic significance of microsatellite instability in colorectal cancer: a Swedish multi-center study

PURPOSE

About 10 to 15% of patients with sporadic colorectal cancer display mutations in DNA mismatch repair (MMR) genes shown as microsatellite instability (MSI). Previous reports of colorectal cancer (CRC) indicate a better prognosis for patients with MSI tumors compared to patients with microsatellite stable (MSS) tumors. In this study, our aim was to investigate whether MSI is an independent prognostic factor in CRC.

PATIENTS AND METHODS

Patients with stage I-III colorectal cancer and subject to curative surgery during 2002-2006 in the Swedish low-risk colorectal cancer study group cohort were eligible for inclusion. Deficient MMR (dMMR) status was analyzed by immunohistochemistry (IHC) and/or by MSI testing with polymerase chain reaction (PCR). Prognostic follow-up and treatment data were retrieved from patient records. Statistical analyses to assess MSI-status and prognosis were done using logistic regression and survival analyses using the Kaplan-Meier method and Cox regression hazards models adjusted for age, sex, stage, comorbidity, and tumor location.

RESULTS

In total, 463 patients were included, MSI high tumors were present in 66 patients (14%), and the remaining 397 were MSS/MSI low. Within 6 years, distant recurrences were present in 9.1% and 20.2% (P = 0.049), and death occurred in 25.8% and 31.5% in MSI and MSS patients, respectively. There was no statistically significant difference in overall mortality (HR 0.80, 95% CI 0.46-1.38), relapse-free survival (HR 0.82, 95% CI 0.50-1.36), or cancer-specific mortality (HR 1.60, 95% CI 0.73-3.51).

CONCLUSION

Despite distant metastases being less common in patients with MSI, there was no association between MSI and overall, relapse-free, or cancer-specific survival.

Prognostic Significance of MRE11 Overexpression in Colorectal Cancer Patients

Meiotic recombination 11 (MRE11) plays a critical role in the DNA damage response and maintenance of genome stability and is associated with the prognosis for numerous malignancies. Here, we explored the clinicopathological significance and prognostic value of MRE11 expression in colorectal cancer (CRC), a leading cause of cancer-related deaths worldwide. Samples from 408 patients who underwent surgery for colon and rectal cancer between 2006 and 2011, including a sub-cohort of 127 (31%) patients treated with adjuvant therapy, were analyzed. In Kaplan-Meier survival analyses, we found that high MRE11 expression in the tumor center (TC) was significantly associated with poor disease-free survival (DFS; p = 0.045) and overall survival (OS; p = 0.039). Intriguingly, high MRE11 expression in the TC was also significantly correlated with reduced DFS (p = 0.005) and OS (p = 0.010) in the subgroup with right-sided primary CRC. In multivariate analyses, high MRE11 expression (hazard ratio [HR] = 1.697, 95% confidence interval [CI]: 1.034-2.785; p = 0.036) and lymphovascular/perineural invasion (LVI/PNI; HR = 1.922, 95% CI 1.122-3.293; p = 0.017) showed significant association with worse OS in patients with right-sided tumors but not those with left-sided tumors. Moreover, in patients with right-sided tumors, high MRE11 was associated with worse OS for those with lymph node involvement (p = 0.006) and LVI/PNI (p = 0.049). Collectively, our results suggest that MRE11 may serve as an independent prognostic marker in those with right-sided severe CRC, with clinical value in the management of these patients.

Biomarkers for chemotherapy and drug resistance in the mismatch repair pathway

Drugs targeting DNA repair have developed rapidly in cancer therapy, and numerous inhibitors have already been utilized in preclinical and clinical stages. To optimize the selection of patients for treatment, it is essential to discover biomarkers to anticipate chemotherapy response. The DNA mismatch repair (MMR) pathway is closely correlated with cancer susceptibility and plays an important role in the occurrence and development of cancers. Here, we give a concise introduction of the MMR genes and focus on the potential biomarkers of chemotherapeutic response and resistance. It has been clarified that the status of MMR may affect the outcome of chemotherapy. However, the specific underlying mechanisms as well as contradictory results continue to raise considerable controversy and concern. In this review, we summarize the current literature to provide a general overview.

Left-Sided Colon Cancer and Right-Sided Colon Cancer: Are They the Same Cancer or Two Different Entities?

Background Colon cancer is one of the most common cancers in the world and one of the main causes of cancer-related deaths. In Morocco, it occupies the first place among digestive cancers. Right-sided and left-sided colon cancers have different embryological, epidemiological, pathological, genetic, and clinical characteristics. This distinction leads to differences in the evolution and prognosis of the disease. This study aimed to identify epidemiological factors and clinical and pathological characteristics that can influence perioperative and prognostic outcomes in patients with right-sided colon cancer compared to those with left-sided colon cancer. Methodology We conducted a retrospective cohort study over a period of nine years from January 2012 until December 2020. We included 277 patients divided into two groups, namely, right colon cancer (group 1) (n = 99) and left colon cancer (group 2) (n = 178). Results The average age of our series was 57.4 years, with extremes ranging from 19 to 89 years old (SD = ±13.6451 years). The average age in the right colon group was 55.97 (SD = ±13.341 years). The average age in the left colon group was 58.18 (SD = ±13.69 years). The male gender had a predominance, with a sex ratio of 1.3 for both groups. Among the patients in group 2, 65% showed lymph node involvement on the CT scan, whereas only 34% of patients in group 1 displayed the same condition. The recurrence rate in the right-sided colon cancer group was 22.2% compared to 24.9% in the left-sided group. The five-year overall survival was estimated for the right-sided and left-sided colon cancer groups at 87% and 96.5%, respectively. In patients with stage III and IV cancer, overall survival was better for those who underwent surgery for left-sided colon cancer compared to those who underwent surgery for right-sided colon cancer (p = 0.029). In the case of vascular emboli or involvement of the perineural sheath, there was no significant difference in overall survival (p = 0.446 and p = 0.655, respectively). The three-month survival without recurrence was almost identical in both groups (31% for right-sided colon cancers and 30.9% for left-sided colon cancers). Age over 61 years was a predictive factor of poor prognosis in recurrence-free survival (hazard ratio = 3.245; p = 0.023). Conclusions We identified factors that can influence perioperative outcomes and prognosis in patients with right-sided colon cancer compared to those with left-sided colon cancer. Our findings suggest that age and lymph node involvement along with other factors play a role in the overall survival and recurrence outcomes of these patients. Further research is necessary to explore these differences and develop personalized treatment plans for patients with colon cancer.

Neoadjuvant Immune Checkpoint Inhibitor Therapy for Patients With Microsatellite Instability-High Colorectal Cancer: Shedding Light on the Future

Immune checkpoint inhibitors (ICIs) have revolutionized the treatment paradigm of mismatch repair-deficient/microsatellite instability-high (MMMR-D/MSI-H) colorectal cancer (CRC). Unique molecular features of MMR-D/MSI-H CRC with frameshift alterations, which result in mutation-associated neoantigen (MANA) generation, create an ideal molecular framework for MANA-driven T-cell priming and antitumor immunity. These biologic characteristics of MMR-D/MSI-H CRC resulted in rapid drug development with ICIs for patients with MMR-D/MSI-H CRC. Observed deep and durable responses with the use of ICIs in advanced-stage disease have stimulated the development of clinical trials with ICIs for patients with early-stage MMR-D/MSI-H CRC. Most recently, neoadjuvant dostarlimab monotherapy for nonoperative management of MMR-D/MSI-H rectal cancer and neoadjuvant NICHE trial with nivolumab and ipilimumab for MMR-D/MSI-H colon cancer resulted in groundbreaking results. Although nonoperative management of patients with MMR-D/MSI-H rectal cancer with ICIs will potentially define our current therapeutic approach, therapeutic goals of neoadjuvant ICI therapy for patients with MMR-D/MSI-H colon cancer may differ given that nonoperative management has not been well established for colon cancer. Herein, we overview recent advancements in ICI-based therapies for patients with early-stage MMR-D/MSI-H colon and rectal cancer and elaborate on the future treatment paradigm of this unique subgroup of CRC.

Emerging evidence of immunotherapy for colorectal cancer

Since the advent of immune checkpoint inhibitors, which modulate the interplay between the tumor cell and immune system, immunotherapy has become widely recognized as a new standard treatment for cancers including microsatellite instability-high (MSI-H) colorectal cancer. Immune checkpoint inhibitors such as pembrolizumab and nivolumab (anti-PD-1 antibodies) that act in the effector phase of T cells and ipilimumab (anti-CTLA-4 antibody) that acts mainly in the priming phase are now in clinical use. These antibodies have shown therapeutic efficacy in MSI colorectal cancer patients who have failed to respond to existing standard therapies. Pembrolizumab is also strongly recommended as first-line therapy for MSI-H metastatic colorectal cancer. Therefore, the MSI status and tumor mutation burden of the tumor should be clarified before starting treatment. Because many patients do not respond to immune checkpoint inhibitors, combination therapies with immune checkpoint inhibitors, including chemotherapy, radiotherapy, or molecularly targeted agents, are being investigated. Furthermore, treatment methods for preoperative adjuvant therapy for rectal cancer are being developed.

Patterns of DNA mismatch repair protein expression for primary and recurrent colorectal cancer at an advanced surgical unit: A retrospective audit

AIM

Lynch syndrome is an inherited cancer syndrome associated with an increased lifetime risk of colorectal cancer (CRC) and characterized by germline mutations to one of four DNA mismatch repair (MMR) genes. Immunohistochemical (IHC) testing is used to screen for Lynch syndrome; however, despite routine completion following resection of primary CRC, it is only variably completed following resection of recurrent disease. This may be significant, as MMR protein expression can change from primary to recurrent CRC. The primary aim of this study is to investigate how MMR profiles change from primary to recurrent CRC; the secondary aim is to assess rates of MMR testing of primary and recurrent disease.

METHOD

We conducted a retrospective analysis of patients undergoing surgery for recurrent CRC from 2018-19 at a high-volume institution. MMR profiles were obtained following both primary and recurrent resection of CRC, and MMR protein expression was evaluated from both time points.

RESULTS

A total of 107 patients met the inclusion criteria and IHC results were obtained for both primary and recurrent resections in 85 cases. MMR profiles changed in nine patients (10.6%), with a loss of staining from primary to recurrent disease in six (7.1%) and a gain of staining in three (3.5%). IHC testing was completed following 88.7% of primary and 39.3% of recurrent resections.

CONCLUSION

MMR profiles can change from primary to recurrent CRC and repeat MMR testing for recurrent CRC is completed in only a minority of cases.

Challenges and Therapeutic Opportunities in the dMMR/MSI-H Colorectal Cancer Landscape

About 5 to 15% of all colorectal cancers harbor mismatch repair deficient/microsatellite instability-high status (dMMR/MSI-H) that associates with high tumor mutation burden and increased immunogenicity. As a result, and in contrast to other colorectal cancer phenotypes, a significant subset of dMMR/MSI-H cancer patients strongly benefit from immunotherapy. Yet, a large proportion of these tumors remain unresponsive to any immuno-modulating treatment. For this reason, current efforts are focused on the characterization of resistance mechanisms and the identification of predictive biomarkers to guide therapeutic decision-making. Here, we provide an overview on the new advances related to the diagnosis and definition of dMMR/MSI-H status and focus on the distinct clinical, functional, and molecular cues that associate with dMMR/MSI-H colorectal cancer. We review the development of novel predictive factors of response or resistance to immunotherapy and their potential application in the clinical setting. Finally, we discuss current and emerging strategies applied to the treatment of localized and metastatic dMMR/MSI-H colorectal tumors in the neoadjuvant and adjuvant setting.

CD8 + T-cell Density Is an Independent Predictor of Survival and Response to Adjuvant Chemotherapy in Stage III Colon Cancer

We assessed CD8 + T-cell density in 351 resected stage II to III colon cancers from 2011 to 2015 and correlated the findings with disease-free survival and survival effect of adjuvant chemotherapy. Most tumors (70%) had high/intermediate CD8 + T-cell density, and this was significantly associated with mismatch repair deficiency compared with tumors with low CD8 + T-cell density (28% vs. 13%, P =0.003). Fewer tumors with high/intermediate CD8 + T-cell density had adverse histologic features compared with tumors with low CD8 + T-cell density including high tumor budding (16% vs. 27%) and venous (22% vs. 35%), lymphatic (54% vs. 65%), and perineural (23% vs. 33%) invasion (all with P <0.05). In the stage III cohort, high/intermediate CD8 + T-cell density was an independent predictor of disease-free survival on multivariate analysis (hazard ratio: 0.39, 0.21 to 0.71 95% CI, P =0.002). For stage III patients with high/intermediate CD8 + T-cell density, adjuvant chemotherapy was significantly associated with improved disease-free survival (hazard ratio: 0.28, 0.11 to 0.74 95% CI, P =0.01) whereas stage III patients with low CD8 + T-cell density did not have improved survival with adjuvant chemotherapy. In conclusion, in stage III colon cancer, CD8 + T-cell density is an independent prognostic biomarker for disease-free survival and may help to identify patients who benefit from adjuvant chemotherapy.

Microsatellite instability is associated with worse overall survival in resectable colorectal liver metastases

BACKGROUND

Microsatellite instability (MSI) has been associated with improved overall survival (OS) in locoregional colorectal cancer; however, the effects on colorectal liver metastases (CRLM) have not been studied.

METHODS

The National Cancer Database (NCDB) was queried for patients with CRLM that underwent metastasectomy. Patients with microsatellite stable tumors (MSS) (n = 2,316, 84.4%) were compared those with MSI (n = 427, 15.6%).

RESULTS

Baseline characteristics, including sex, race, and underlying comorbidities, were similar between groups. MSS patients had lower rates of high-risk pathologic features and higher rates of receiving multi-agent chemotherapy. On Kaplan-Meier analysis, median OS in the MSS group was improved compared with the MSI group (41.1 mo vs. 33.2 mo, p < 0.01). On multivariate analysis MSI status remained associated with worse OS (HR: 1.21 95% CI: 1.01-1.46, p = 0.04).

CONCLUSIONS

This national analysis of CRLM validates MSI status as a biomarker to guide clinical decision-making due to the associated poor prognosis.

Alarmin IL-33 orchestrates antitumoral T cell responses to enhance sensitivity to 5-fluorouracil in colorectal cancer

Rationale: Resistance to 5-fluorouracil (5-FU) chemotherapy remains the main barrier to effective clinical outcomes for patients with colorectal cancer (CRC). A better understanding of the detailed mechanisms underlying 5-FU resistance is needed to increase survival. Interleukin (IL)-33 is a newly discovered alarmin-like molecule that exerts pro- and anti-tumorigenic effects in various cancers. However, the precise role of IL-33 in CRC progression, as well as in the development of 5-FU resistance, remains unclear. Methods: High-quality RNA-sequencing analyses were performed on matched samples from patients with 5-FU-sensitive and 5-FU-resistant CRC. The clinical and biological significance of IL-33, including its effects on both T cells and tumor cells, as well as its relationship with 5-FU chemotherapeutic activity were examined in ex vivo, in vitro and in vivo models of CRC. The molecular mechanisms underlying these processes were explored. Results: IL-33 expressed by tumor cells was a dominant mediator of antitumoral immunity in 5-FU-sensitive patients with CRC. By binding to its ST2 receptor, IL-33 triggered CD4+ (Th1 and Th2) and CD8+ T cell responses by activating annexin A1 downstream signaling cascades. Mechanistically, IL-33 enhanced the sensitivity of CRC cells to 5-FU only in the presence of T cells, which led to the activation of both tumor cell-intrinsic apoptotic and immune killing-related signals, thereby synergizing with 5-FU to induce apoptosis of CRC cells. Moreover, injured CRC cells released more IL-33 and the T cell chemokines CXCL10 and CXCL13, forming a positive feedback loop to further augment T cell responses. Conclusions: Our results identified a previously unrecognized connection between IL-33 and enhanced sensitivity to 5-FU. IL-33 created an immune-active tumor microenvironment by orchestrating antitumoral T cell responses. Thus, IL-33 is a potential predictive biomarker for 5-FU chemosensitivity and favorable prognosis and has potential as a promising adjuvant immunotherapy to improve the clinical benefits of 5-FU-based therapies in the treatment of CRC.

Anti-Programmed Cell Death-1 Antibody and Dasatinib Combination Therapy Exhibits Efficacy in Metastatic Colorectal Cancer Mouse Models

In this study, we investigated the in vivo metastasis suppression effects of the platelet-derived growth factor receptor inhibitor dasatinib, which targets cancer-associated fibroblasts (CAFs), in combination with an anti-programmed cell death-1 (PD-1) antibody. We classified clinical CRC cases as inflamed, excluded, or desert using immunohistochemical analysis and evaluated the tumor stroma. The excluded type was the most common, and cases with high-volume stroma in the primary lesions also had a high stromal volume in the liver metastatic lesions. Liver-metastasis mouse models with different stromal volumes were established and treatment-induced changes in the tumor immune microenvironment were evaluated. The anti-PD-1 antibody alone exhibited a therapeutic effect for the liver metastases with low stromal volumes but not for the liver metastases with high stromal volumes. In contrast, antitumor effects were observed with anti-PD-1 antibody/dasatinib combination therapy even in the liver metastases with high stromal volumes. Combination therapy reduced the stromal volume, promoted immune cell infiltration, induced antitumor cytotoxic T-cell responses, activated antitumor immunity, and promoted tumor regression. These results suggest that CAFs play an important role in the immune evasion of CRC and that anti-PD-1 antibody/dasatinib combination therapy has potential as a treatment option for patients with metastatic CRC for whom immunotherapy alone is ineffective.

The distinct clinical trajectory, metastatic sites, and immunobiology of microsatellite-instability-high cancers

Microsatellite-instability-high (MSI-H) cancers form a spectrum of solid organ tumors collectively known as Lynch Syndrome cancers, occurring not only in a subset of colorectal, endometrial, small bowel, gastric, pancreatic, and biliary tract cancers but also in prostate, breast, bladder, and thyroid cancers. Patients with Lynch Syndrome harbor germline mutations in mismatch repair genes, with a high degree of genomic instability, leading to somatic hypermutations and, therefore, oncogenesis and cancer progression. MSI-H cancers have unique clinicopathological characteristics compared to their microsatellite-stable (MSS) counterparts, marked by a higher neoantigen load, immune cell infiltration, and a marked clinical response to immune checkpoint blockade. Patients with known Lynch Syndrome may be detected early through surveillance, but some patients present with disseminated metastatic disease. The treatment landscape of MSI-H cancers, especially colorectal cancers, has undergone a paradigm shift and remains to be defined, with immune checkpoint blockade coming to the forefront of treatment strategies in the stage IV setting. We summarize in this review the clinical features of MSI-H cancers with a specific interest in the pattern of spread or recurrence, disease trajectory, and treatment strategies. We also summarize the tumor-immune landscape and genomic profile of MSI-H cancers and potential novel therapeutic strategies.

Metabolic activity via 18F-FDG PET/CT is predictive of microsatellite instability status in colorectal cancer

Purpose

Identification of microsatellite instability high (MSI-H) colorectal cancer (CRC) is crucial for screening patients most likely to benefit from immunotherapy. We aim to investigate whether the metabolic characteristics is related to MSI status and can be used to predict the MSI-H CRC.

Methods

A retrospective analysis was conducted on 420 CRC patients who were identified via [¹⁸F]fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET)/computed tomography(CT) prior to therapy. Maximum standardized uptake (SUV_max), mean standardized uptake (SUV_mean), metabolic tumor volume (MTV) and total lesion glycolysis (TLG) of the primary tumor were calculated and compared between MSI-H and microsatellite stability (MSS). Predictive factors of MSI status were selected from metabolic parameters and clinicopathological profiles via a multivariate analysis.

Results

Of 420 colorectal cancers, 44 exhibited a high incidence of MSI. Both MTV and TLG were significantly higher in MSI-H group compared with the MSS group (P = 0.004 and P = 0.010, respectively). Logistic regression analysis indicated that CRC with MSI-H were related to younger age (P = 0.013), primary lesion located at right hemi-colon (P < 0.001) and larger MTV on PET/CT imaging (P = 0.019). MTV more than 32.19 of colorectal cancer was linked to the presence of MSI (P = 0.019).

Conclusion

Tumor metabolic burden were higher in MSI-H CRC which may be useful for predicting the MSI status of CRC patient and thus aid in determination of immunotherapy for patients with CRC.

Comprehensive Review of Biomarkers for the Treatment of Locally Advanced Colon Cancer

Despite the implementation of global screening programs, colorectal cancer (CRC) remains the second leading cause of cancer-related deaths worldwide. More than 10% of patients with colon cancer are diagnosed as having locally advanced disease with a relatively poor five-year survival rate. Locally advanced colon cancer (LACC) presents surgical challenges to R0 resection. The advantages and disadvantages of preoperative radiotherapy for LACC remain undetermined. Although several reliable novel biomarkers have been proposed for the prediction and prognosis of CRC, few studies have focused solely on the treatment of LACC. This comprehensive review highlights the role of predictive biomarkers for treatment and postoperative oncological outcomes for patients with LACC. Moreover, this review discusses emerging needs and approaches for the discovery of biomarkers that can facilitate the development of new therapeutic targets and surveillance of patients with LACC.

Identification of BGN and THBS2 as metastasis-specific biomarkers and poor survival key regulators in human colon cancer by integrated analysis

BACKGROUND

Colon cancer is the second leading cause of death worldwide. Exploring key regulators in colon cancer metastatic progression could lead to better outcomes for patients.

METHODS

Initially, the transcriptional profiles of 681 colonrectal cancer (CRC) cases were used to discover signature genes that were significantly correlated with colon cancer metastasis. These signature genes were then validated using another independent 210 CRC cases' transcriptomics and proteomics profiles, and Kaplan-Meier regression analyses were used to screen the key regulators with patients' survival. Immunohistochemical staining was used to confirm the biomarkers, and transit knockdown was used to explore their implications on colon cancer cells migration and invasion abilities. The impact on the key signalling molecules in epithelial-mesenchymal transition (EMT) process that drive tumour metastasis was tested using Western blot. The response to clinical standard therapeutic drugs was compared to clinical prognosis of key regulators using an ROC plotter.

RESULTS

Five genes (BGN, THBS2, SPARC, CDH11 and SPP1) were initially identified as potential biomarkers and therapeutic targets of colon cancer metastasis. The most significant signatures associated with colon cancer metastasis were determined to be BGN and THBS2. Furthermore, highly expression of BGN and THBS2 in tumours was linked to a worse survival rate. BGN and THBS2 knockdown significantly reduced colon cancer cells migration and invasion, as well as down-regulating three EMT-related proteins (Snail, Vimentin and N-cadherin), and increasing the proliferation inhibitory effect of 5-fluorouracil, irinotecan and oxaliplatin treatment.

CONCLUSIONS

CRC metastatic progression, EMT phenotypic transition and poor survival time have been linked to BGN and THBS2. They could be utilized as potential diagnostic and therapeutic targets for colon cancer metastatic patients with a better prognosis.

Correlation of Immunological and Histopathological Features with Gene Expression-Based Classifiers in Colon Cancer Patients

The purpose of this study was to evaluate the association between four distinct histopathological features: (1) tumor infiltrating lymphocytes, (2) mucinous differentiation, (3) tumor-stroma ratio, plus (4) tumor budding and two gene expression-based classifiers—(1) consensus molecular subtypes (CMS) plus (2) colorectal cancer intrinsic subtypes (CRIS). All four histopathological features were retrospectively scored on hematoxylin and eosin sections of the most invasive part of the primary tumor in 218 stage II and III colon cancer patients from two independent cohorts (AMC-AJCC-90 and AC-ICAM). RNA-based CMS and CRIS assignments were independently obtained for all patients. Contingency tables were constructed and a χ2 test was used to test for statistical significance. Odds ratios with 95% confidence intervals were calculated. The presence of tumor infiltrating lymphocytes and a mucinous phenotype (>50% mucinous surface area) were strongly correlated with CMS1 (p < 0.001 and p = 0.008) and CRIS-A (p = 0.006 and p < 0.001). The presence of mucus (≥ 10%) was associated with CMS3: mucus was present in 64.1% of all CMS3 tumors (p < 0.001). Although a clear association between tumor-stroma ratio and CMS4 was established in this study (p = 0.006), still 32 out of 61 (52.5%) CMS4 tumors were scored as stroma-low, indicating that CMS4 tumors cannot be identified solely based on stromal content. Higher budding counts were seen in CMS4 and CRIS-B tumors (p = 0.045 and p = 0.046). No other associations of the measured parameters were seen for any of the other CRIS subtypes. Our analysis revealed clear associations between histopathologic features and CMS or CRIS subtypes. However, identification of distinct molecular subtypes solely based on histopathology proved to be infeasible. Combining both molecular and morphologic features could potentially improve patient stratification.

Use of Personalized Biomarkers in Metastatic Colorectal Cancer and the Impact of AI

Colorectal cancer is a major cause of cancer-related death worldwide and is correlated with genetic and epigenetic alterations in the colonic epithelium. Genetic changes play a major role in the pathophysiology of colorectal cancer through the development of gene mutations, but recent research has shown an important role for epigenetic alterations. In this review, we try to describe the current knowledge about epigenetic alterations, including DNA methylation and histone modifications, as well as the role of non-coding RNAs as epigenetic regulators and the prognostic and predictive biomarkers in metastatic colorectal disease that can allow increases in the effectiveness of treatments. Additionally, the intestinal microbiota’s composition can be an important biomarker for the response to strategies based on the immunotherapy of CRC. The identification of biomarkers in mCRC can be enhanced by developing artificial intelligence programs. We present the actual models that implement AI technology as a bridge connecting ncRNAs with tumors and conducted some experiments to improve the quality of the model used as well as the speed of the model that provides answers to users. In order to carry out this task, we implemented six algorithms: the naive Bayes classifier, the random forest classifier, the decision tree classifier, gradient boosted trees, logistic regression and SVM.

Deficient mismatch repair/microsatellite unstable colorectal cancer: Diagnosis, prognosis and treatment

Microsatellite unstable (MSI) colorectal cancers (CRCs) are due to DNA mismatch repair (MMR) deficiency and occurs in15% of non-metastatic diseases and 5% in the metastatic setting. Nearly 30% of MSI CRCs occur in a context of constitutional mutation of the MMR system (Lynch syndrome). Others are sporadic cancers linked to a hypermethylation of the MLH-1 promoter. The pathogenic alterations of MMR genes lead to the accumulation of frequent somatic mutational events and these tumours arbour a high antigen burden and are highly infiltrated with cytotoxic T-cell lymphocytes. Microsatellite instability/DNA mismatch repair deficiency (MSI/dMMR) status has prognostic and predictive implications in non-metastatic and metastatic CRCs. The prognostic value of MSI status in non-metastatic CRCs has been studied extensively, yet the data are more limited for its predictive value in terms of adjuvant chemotherapy efficacy. In both cases (metastatic and non-metastatic settings) treatment with immune check-point inhibitors (ICIs) have shown a remarkable effectiveness in the context of MSI/dMMR status. Indeed, recent data from prospective cohorts and randomised trials have shown a dramatical improvement of survival with immunotherapy (programmed death-ligand 1 [PD-(L)1]   cytotoxic T-lymphocyte-associated antigen 4 [CTLA-4] blockage) in metastatic or non-metastatic MSI/dMMR CRC. In this review we report and discuss how and for whom to test for the MSI/dMMR phenotype, as well as the prognostic value of this phenotype and the new treatment recommendations options for this unique CRC population. Despite their efficacy, primary and secondary resistance to immune checkpoint inhibitors (ICIs) are observed in more than 50% MSI-H/dMMR CRC patients and in the future how to identify these patients and to overcome resistance will be an important challenge.

Early-Onset Cancers in Adults: A Review of Epidemiology, Supportive Care Needs and Future Research Priorities

Rising incidence of specific types of early-age onset cancers in adults aged 18-49 years has been reported in high-income countries. In this review, we summarise the epidemiology of early-onset cancers using exemplar data from a high-income UK region, discuss supportive care needs for young patients and outline future research directions. The incidence rate of early-onset cancers increased by 20.5% from 1993 to 2019 in Northern Ireland. Differences in types of cancer were observed between sexes and across age groups of 18-29, 30-39 and 40-49 years. One and five-year net survival was mostly better in 18-29-year-olds for all cancers combined compared to older age groups for both sexes, but there were variations in specific cancer types. Poorer survival was observed for patients with brain/central nervous system, connective and soft tissue or lung cancers. Patients with early-onset cancers face unique supportive care needs and require holistic care. The impact of cancer treatment on fertility and fertility preservation treatments is an important consideration. Social media can be used for patient support, information, fundraising, advocacy work and recruitment to research studies. We also outline suggested future research priorities for early-onset cancers, spanning prevention, diagnosis, treatment and supportive care needs.

Histomorphological and molecular genetic characterization of different intratumoral regions and matched metastatic lymph nodes of colorectal cancer with heterogenous mismatch repair protein expression

PURPOSE

To better understand the clinicopathological characteristics and molecular alterations in different intratumoral components of colorectal cancer (CRC) with heterogeneity of mismatch repair (MMR) protein expression and microsatellite instability (MSI) status.

METHODS

The histopathological features, MSI status, and other molecular alterations were analyzed in separately microdissected intratumoral regions and matched metastatic lymph nodes in four cases with intratumoral heterogenous MMR expression screened from 500 CRC patients, using PCR-based MSI testing, MLH1 promoter methylation, and targeted next-generation sequencing (NGS).

RESULTS

High microsatellite instability (MSI-H) was identified in MLH1/PMS2-deficient regions in Cases 1 to 3 and in MSH2/MSH6-deficient regions in Case 4, while microsatellite stability (MSS) was detected in all the intratumoral regions and metastatic lymph nodes with proficient MMR expression (pMMR). Intratumoral heterogeneity of MLH1 promoter methylation and/or other common driving gene mutations of CRC, such as KRAS and PIK3CA mutations, was identified in all four CRCs. Further, three cases (75%) showed heterogeneous histomorphological features in intratumoral components and metastatic lymph nodes (Cases 1, 2, and 4), and the corresponding metastatic lymph nodes showed moderate differentiation with MSS/pMMR (Cases 2 and 3).

CONCLUSIONS

Intratumoral heterogeneous MSI status is highly correlated with intratumoral histomorphological heterogeneity, which is also an important clue for the intratumoral heterogeneity of drive gene mutations in CRC. Thus, it is essential to detect MMR protein expression and other gene mutations in metastases before treatment, especially for CRCs with intratumoral heterogenous MMR protein expression or heterogenous histomorphological features.

Discordant prognosis of mismatch repair deficiency in colorectal and endometrial cancer reflects variation in antitumour immune response and immune escape

Defective DNA mismatch repair (dMMR) causes elevated tumour mutational burden (TMB) and microsatellite instability (MSI) in multiple cancer types. dMMR/MSI colorectal cancers (CRCs) have enhanced T-cell infiltrate and favourable outcome; however, this association has not been reliably detected in other tumour types, including endometrial cancer (EC). We sought to confirm this and explore the underpinning mechanisms. We first meta-analysed CRC and EC trials that have examined the prognostic value of dMMR/MSI and confirmed that dMMR/MSI predicts better prognosis in CRC, but not EC, with statistically significant variation between cancers (hazard ratio [HR] = 0.63, 95% confidence interval [CI] = 0.54-0.73 versus HR = 1.15, 95% CI = 0.72-1.58; PINT  = 0.02). Next, we studied intratumoural immune infiltrate in CRCs and ECs of defined MMR status and found that while dMMR was associated with increased density of tumour-infiltrating CD3+ and CD8+ T-cells in both cancer types, the increases were substantially greater in CRC and significant only in this group (PINT  = 4.3e-04 and 7.3e-03, respectively). Analysis of CRC and EC from the independent Cancer Genome Atlas (TCGA) series revealed similar variation and significant interactions in proportions of tumour-infiltrating lymphocytes, CD8+ , CD4+ , NK cells and immune checkpoint expression, confirming a more vigorous immune response to dMMR/MSI in CRC than EC. Agnostic analysis identified the IFNγ pathway activity as strongly upregulated by dMMR/MSI in CRC, but downregulated in EC by frequent JAK1 mutations, the impact of which on IFNγ response was confirmed by functional analyses. Collectively, our results confirm the discordant prognosis of dMMR/MSI in CRC and EC and suggest that this relates to differences in intratumoural immune infiltrate and tumour genome. Our study underscores the need for tissue-specific analysis of cancer biomarkers and may help inform immunotherapy use. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Immune Response in Colorectal Carcinoma: A Review of Its Significance as a Predictive and Prognostic Biomarker

Colorectal carcinoma is a leading cause of cancer-related death worldwide. There is significant prognostic heterogeneity in stage II and III tumours, necessitating the development of new biomarkers to better identify patients at risk of disease progression. Recently, the tumour immune environment, particularly the type and quantity of T lymphocytes, has been shown to be a useful biomarker in predicting prognosis for patients with colorectal carcinoma. In this review, the significance of the immune response in colorectal carcinoma, including its influence on prognosis and response to therapy, will be detailed.

Impact of microsatellite status in early-onset colonic cancer

BACKGROUND

The molecular profile of early-onset colonic cancer is undefined. This study evaluated clinicopathological features and oncological outcomes of young patients with colonic cancer according to microsatellite status.

METHODS

Anonymized data from an international collaboration were analysed. Criteria for inclusion were patients younger than 50 years diagnosed with stage I-III colonic cancer that was surgically resected. Clinicopathological features, microsatellite status, and disease-specific outcomes were evaluated.

RESULTS

A total of 650 patients fulfilled the criteria for inclusion. Microsatellite instability (MSI) was identified in 170 (26.2 per cent), whereas 480 had microsatellite-stable (MSS) tumours (relative risk of MSI 2.5 compared with older patients). MSI was associated with a family history of colorectal cancer and lesions in the proximal colon. The proportions with pathological node-positive disease (45.9 versus 45.6 per cent; P = 1.000) and tumour budding (20.3 versus 20.5 per cent; P = 1.000) were similar in the two groups. Patients with MSI tumours were more likely to have BRAF (22.5 versus 6.9 per cent; P < 0.001) and KRAS (40.0 versus 24.2 per cent; P = 0.006) mutations, and a hereditary cancer syndrome (30.0 versus 5.0 per cent; P < 0.001; relative risk 6). Five-year disease-free survival rates in the MSI group were 95.0, 92.0, and 80.0 per cent for patients with stage I, II, and III tumours, compared with 88.0, 88.0, and 65.0 per cent in the MSS group (P = 0.753, P = 0.487, and P = 0.105 respectively).

CONCLUSION

Patients with early-onset colonic cancer have a high risk of MSI and defined genetic conditions. Those with MSI tumours have more adverse pathology (budding, KRAS/BRAF mutations, and nodal metastases) than older patients with MSI cancers.

DNA Mismatch Repair-deficient Rectal Cancer Is Frequently Associated With Lynch Syndrome and With Poor Response to Neoadjuvant Therapy

We evaluated 368 consecutively resected rectal cancers with neoadjuvant therapy for DNA mismatch repair (MMR) protein status, tumor response to neoadjuvant therapy, histopathologic features, and patient survival. Nine (2.4%) rectal cancers were mismatch repair-deficient (MMRD): 8 (89%) Lynch syndrome-associated tumors and 1 (11%) sporadic MLH1-deficient tumor. Of the 9 MMRD rectal cancers, 89% (8/9) had a tumor regression score 3 (poor response) compared with 23% (81/359) of MMR proficient rectal cancers (P<0.001). Patients with MMRD rectal cancer less often had downstaging after neoadjuvant therapy compared with patients with MMR proficient rectal cancer (11% vs. 57%, P=0.007). In the multivariable logistic regression analysis, MMRD in rectal cancer was associated with a 25.11-fold increased risk of poor response to neoadjuvant therapy (tumor regression score 3) (95% confidence interval [CI]: 3.08-44.63, P=0.003). In the multivariable Cox regression analysis, the only variables significantly associated with disease-free survival were pathologic stage III disease (hazard ratio [HR]=2.46, 95% CI: 1.54-3.93, P<0.001), College of American Pathologists (CAP) tumor regression score 2 to 3 (HR=3.44, 95% CI: 1.76-6.73, P<0.001), and positive margins (HR=2.86, 95% CI: 1.56-5.25, P=0.001). In conclusion, we demonstrated that MMRD in rectal cancer is an independent predictor of poor response to neoadjuvant therapy and infrequently results in pathologic downstaging following neoadjuvant therapy. We also confirmed that MMRD in rectal cancer is strongly associated with a diagnosis of Lynch syndrome. Our results suggest that MMR status may help to provide a more patient-centered approach when selecting neoadjuvant treatment regimens and may help predict tumor response to neoadjuvant therapy.

Synergistic antitumor activity of 5-fluorouracil and atosiban against microsatellite stable colorectal cancer through restoring GATA3

Clinically, 5-fluorouracil (5-Fu) is a first-line drug for the treatment of patients with colorectal cancer (CRC). However, chemoresistance to 5-Fu-based chemotherapy is a leading obstacle in achieving effective treatment for CRC, especially microsatellite stable (MSS) CRC. Since the cytotoxicity of 5-Fu is negatively correlated with oxytocin receptor (OXTR) expression in MSS CRC cell lines, our current study aimed to investigate the synergistic antitumor activity of 5-Fu combined with atosiban, an antagonist of OXTR. Our results suggested that atosiban remarkably potentiated the inhibitory effect of 5-Fu on the growth of MSS-type CRC cells in vitro and in vivo. Moreover, 5-Fu induced GATA3 in MSS CRC cells and tumors, which were eradicated by atosiban. Further investigation showed that atosiban strengthened the antitumor activity of 5-Fu through eradiation of 5-Fu-induced GATA3 in MSS-type CRC cells. Taken together, our findings suggest that atosiban potentiates the antitumor effect of 5-Fu by abolishing 5-Fu-induced GATA3, which provides a novel therapeutic strategy for MSS-type CRC via the combination of atosiban and 5-Fu.

Oncotype DX testing does not affect clinical practice in stage IIa colon cancer

Although studies have demonstrated the 12-gene Oncotype DX Colon Recurrence Score's (RS) validity in predicting recurrence and influence on physician-patient decision-making, its discriminatory power and inability to predict response to treatment make its clinical impact uncertain. We sought to evaluate the influence of RS in the decision to offer adjuvant chemotherapy after resection of stage IIa colon cancer. A review of patients with stage IIa colon cancer who obtained the RS at a tertiary academic medical center was conducted. The main study outcome was decision to start adjuvant chemotherapy. The association between RS and the decision to obtain adjuvant chemotherapy was evaluated utilizing the Wilcoxon rank-sum test and area under the receiver operating characteristic curve. 52 of 105 patients with stage IIa colon cancer underwent RS testing. Overall, seven of 52 patients (13%) received adjuvant chemotherapy. 34 (65%) patients obtained the RS test despite having multiple other recurrence risk factors. There were no significant associations between any patient/tumor characteristic and RS score (all p > 0.08) or starting adjuvant chemotherapy (all p > 0.15). On multivariable analysis, there was no significant effect of RS on the odds of undergoing chemotherapy (OR 1.07, 95% CI 0.98-1.19; p = 0.14). There was no clear association between RS and starting adjuvant chemotherapy (AUC 0.64, 95% CI 0.36-0.91; p = 0.25). RS was not associated with the decision to start adjuvant chemotherapy. Given its lack of association with clinical decision-making and inability to predict clinical outcome, our data suggest the RS should not be obtained in patients with stage IIa colon cancer.

MLH1 mediates cytoprotective nucleophagy to resist 5-Fluorouracil-induced cell death in colorectal carcinoma

Colorectal Cancer (CRC) with Microsatellite instability (MSI) and mutLhomolog-1 (MLH1) gene deficiency are less aggressive than MLH1 proficient cancers. MLH1 is involved in several cellular processes, but its connection with the autophagy-dependent cellular response towards anticancer drugs remains unclear. In this study, we aimed to investigate the interaction between MLH1 and the autophagy marker LC3, which facilitated nucleophagy induction, and its potential role in determining sensitivity to 5-Fluorouracil (5-FU) induced cell death. To examine the role of MLH1 in DNA-damage-induced nucleophagy in CRC cells, we utilized a panel of MLH1 deficient and MLH1 proficient CRC cell lines. We included a parental HCT116 cell line (MLH1-/-) and its isogenic cell line HCT116 MLH1+/- in which a single allele of the MLH1 gene was introduced using CRISPR-Cas9 gene editing. We observed that MLH1 proficient cells were less sensitive to the 5-FU-induced cytotoxic effect. The 5-FU induced DNA damage led to LC3 up-regulation, which was dependent on MLH1 overexpression. Moreover, immunofluorescence and immunoprecipitation data showed LC3 and MLH1 were colocalized in CRC cells. Consequently, MLH1 dependent 5-FU-induced DNA damage contributed to the formation of micronuclei. These micronuclei colocalize with autolysosome, indicating a cytoprotective role of MLH1 dependent nucleophagy. Interestingly, siRNA knockdown of MLH1 in HCT116 MLH1+/- prevented LC3 upregulation and micronuclei formation. These novel data are the first to show an essential role of MLH1 in mediating the chemoresistance and survival of cancer cells by increasing the LC3 expression and inducing nucleophagy in 5-FU treated CRC cells.

Survival benefit with adjuvant chemotherapy in stage III microsatellite-high/deficient mismatch repair colon cancer: a systematic review and meta-analysis

Clinical observations have demonstrated that microsatellite instability-high (MSI-H) and/or deficient MMR (dMMR) status are associated with favorable prognosis and no benefit from 5-Fluorouracil (5-FU)-based adjuvant chemotherapy in patients with resected stage II colorectal cancer (CRC). This study represents a systematic review and meta-analysis exploring the predictive role of MSI-H status in stage III CRC undergoing or not adjuvant chemotherapy. Published articles that evaluated the role of adjuvant chemotherapy in resected stage III CRC from inception to September 2020 were identified by searching the PubMed, EMBASE, and Cochrane Library databases. The random-effects model was conducted to estimate the pooled effect size of OS and DFS. The primary outcome of interest was OS. 21,590 patients with MSI-H/dMMR stage III CRC, from n = 17 retrospective studies, were analyzed. Overall, OS was improved with any adjuvant chemotherapy vs. any control arm (single-agent 5-FU or surgery alone): HR 0.42, 95% CI 0.26–0.66; P < 0.01. Conversely, DFS was not significantly improved (HR 0.7, 95% CI 0.45–1.09; P = 0.11). In patients with stage III MSI-H/dMMR CRC, adjuvant chemotherapy is associated with a significant OS improvement. Thus, MSI-H/dMMR status does represent a predictive factor for postoperative chemotherapy benefit in stage III CRC beyond its prognostic role.

Preoperative Neutrophil-BMI Ratio As a Promising New Marker for Predicting Tumor Outcomes in Colorectal Cancer

Background: Inflammation and nutritional status are highly associated with colorectal cancer (CRC) prognosis. This study aimed to evaluate the prognostic value of the preoperative neutrophil-BMI ratio (NBR) in patients with CRC. Methods: A retrospective analysis was performed on 2471 patients with CRC who underwent surgical resection between 2004 and 2019. Patients were divided into two groups based on the cutoff value for NBR. Cox regression and Kaplan–Meier curves were used to evaluate overall survival (OS). Results: High NBR was associated with female sex, low BMI, colon, right-sided CRC, poor differentiation, T3 to 4 stage, M1 to 2 stage, high carcinoembryonic antigen (CEA) level, III-IV stage, microsatellite instability (MSI), and no adjuvant chemotherapy (all P < .05). The high NBR group had a shorter OS than the low NBR group. Female and right sided patients with CRC and with high NBR had a worse prognosis. Univariate Cox regression suggested that NBR was significantly associated with poor prognosis. Multivariate analysis confirmed that age (P = .019,HR:1.012), differentiation (P = .001,HR:1.306), TNM stage (P < .001,HR:2.432), CEA (P = .014,HR:1.001), and NBR (P < .001, HR: 3.309) were independent poor prognostic factors for OS. Subgroup univariate analysis indicated that female patients with high NBR had a worse prognosis. A nomogram composed of TNM stage, CEA, and NBR was developed, and internal validation was based on female patients with CRC. The nomogram provided good discrimination for both the training and validation sets, with area under the curve values of 0.79 and 0.769, respectively. Conclusions: High preoperative levels of NBR are indicators of poor prognosis in patients with CRC.

Sustainable Clinical Development of Adjuvant Chemotherapy for Colon Cancer

Numerous clinical studies in an adjuvant setting have been conducted and the combination therapy of 5-fluorouracil and oxaliplatin has been established as the standard treatment for Stage III and as an option for high-risk Stage II patients. Biologics such as bevacizumab and antiepidermal growth factor receptor antibodies have failed to show additional survival benefits. The indication of adjuvant chemotherapy has been determined according to the pathological stage. Nevertheless, a pathological diagnosis does not necessarily result in selection of the optimal treatment. To improve treatment decisions, many trials have aimed to stratify patients into treatment groups using genomic testing. Recently, gene signature, Immunoscore, and circulating tumor DNA (ctDNA) assays have been reported and among them, ctDNA was shown to be a promising accurate predictive marker for recurrence. Treatment of ctDNA-positive patients with aggressive chemotherapy may reduce recurrence rates. The ultimate goal is to accurately predict the risk of recurrence and to prevent recurrence in colon cancer patients. In this review we focus on the clinical development of adjuvant chemotherapy and stratification of patients according to risk of recurrence and the future direction of adjuvant chemotherapy.

The potential role of miR-1290 in cancer progression, diagnosis, prognosis, and treatment: An oncomiR or onco-suppressor microRNA?

Cancer is one of the leading causes of death in humans because of the lack of early diagnosis, distant metastases, and the resistance to adjuvant therapies, including chemotherapy and radiotherapy. In addition to playing an essential role in tumor progression and development, microRNAs (miRNAs) can be used as a robust biomarker in the early detection of cancer. MiR-1290 was discovered for the first time in human embryonic stem cells, and under typical physiological situations, plays an essential role in neuronal differentiation and neural stem cell proliferation. Its coding sequence is located at the 1p36.13 regions in the first intron of the aldehyde dehydrogenase 4 gene member A1. miR-1290 is out of control in many cancers such as breast cancer, colorectal cancer, esophageal squamous cell carcinoma, gastric cancer, lung cancer, pancreatic cancer, and plays a vital role in their development. Therefore, it is suggested that miR-1290 can be considered as a potential diagnostic and therapeutic target in many cancers. In addition to the importance of miR-1290 in the noninvasive diagnosis of various cancers, this systematic review study discussed the role of miR-1290 in altering the expression of different genes involved in cancer development and chemo-radiation resistance. Moreover, it considered the regulatory effect of natural products on miR-1290 expression and the interaction of lncRNAs by miR-1290.

Defects in MMR Genes as a Seminal Example of Personalized Medicine: From Diagnosis to Therapy

Microsatellite instability (MSI) is the landmark feature of DNA mismatch repair deficiency, which can be found in 15-20% of all colorectal cancers (CRC). This specific set of tumors has been initially perceived as a niche for geneticists or gastroenterologists focused on inherited predispositions. However, over the years, MSI has established itself as a key biomarker for the diagnosis, then extending to forecasting the disease behavior and prognostication, including the prediction of responsiveness to immunotherapy and eventually to kinase inhibitors, and possibly even to specific biological drugs. Thanks to the contribution of the characterization of MSI tumors, researchers have first acknowledged that a strong lymphocytic reaction is associated with a good prognosis. This understanding supported the prognostic implications in terms of the low metastatic potential of MSI-CRC and has led to modifications in the indications for adjuvant treatment. Furthermore, with the emergence of immunotherapy, this strong biomarker of responsiveness has exemplified the capability of re-activating an effective immune control by removing the brakes of immune evasion. Lately, a subset of MSI-CRC emerged as the ideal target for kinase inhibitors. This therapeutic scenario implies a paradox in which appropriate treatments for advanced disease are effective in a set of tumors that seldom evolve towards metastases.

Pan-Asian adapted ESMO Clinical Practice Guidelines for the diagnosis treatment and follow-up of patients with localised colon cancer

The most recent version of the European Society for Medical Oncology (ESMO) Clinical Practice Guidelines for the diagnosis, treatment and follow-up of localised colon cancer was published in 2020. It was decided by both the ESMO and the Japanese Society of Medical Oncology (JSMO) to convene a special virtual guidelines meeting in March 2021 to adapt the ESMO 2020 guidelines to take into account the ethnic differences associated with the treatment of localised colon cancer in Asian patients. These guidelines represent the consensus opinions reached by experts in the treatment of patients with localised colon cancer representing the oncological societies of Japan (JSMO), China (CSCO), India (ISMPO), Korea (KSMO), Malaysia (MOS), Singapore (SSO) and Taiwan (TOS). The voting was based on scientific evidence and was independent of the current treatment practices and drug availability and reimbursement situations in the different Asian countries.

The therapeutic and prognostic implications of immunobiology in colorectal cancer: a review

Colorectal cancer represents the second leading cause of cancer-related death worldwide. The therapeutic field of immuno-oncology has rapidly gained momentum, with strikingly promising results observed in clinical practice. Increasing emphasis has been placed on the role of the immune response in tumorigenesis, therapy and predicting prognosis. Enhanced understanding of the dynamic and complex tumour-immune microenvironment has enabled the development of molecularly directed, individualised treatment. Analysis of intra-tumoural lymphocyte infiltration and the dichotomisation of colorectal cancer into microsatellite stable and unstable disease has important therapeutic and prognostic implications, with potential to capitalise further on this data. This review discusses the latest evidence surrounding the tumour biology and immune landscape of colorectal cancer, novel immunotherapies and the interaction of the immune system with each apex of the tripartite of cancer management (oncotherapeutics, radiotherapy and surgery). By utilising the synergy of chemotherapeutic agents and immunotherapies, and identifying prognostic and predictive immunological biomarkers, we may enter an era of unprecedented disease control, survivorship and cure rates.

Prognostic Significance of Preoperative Globulin-to-albumin Ratio in Obstructive Colorectal Cancer Patients Who Underwent Curative Surgery after Stenting

Objectives:

It has been increasingly recognized that the progression of cancer is dependent not only on the tumor characteristics but also on the nutritious and inflammatory condition of the host. We investigated the relationship between the globulin-to-albumin ratio (GAR) and long-term outcomes in obstructive colorectal cancer (OCRC) patients who were inserted self-expandable metallic stent as a bridge to curative surgery.

Methods:

A total of 75 pathological stage II and III OCRC patients between 2013 and 2020 were retrospectively evaluated. The associations of the preoperative GAR with clinicopathological factors and patient survival were examined.

Results:

Receiver operating characteristic curve analysis demonstrated that the optimal cutoff value was 0.88. The GAR ≥ 0.88 status was significantly associated with the absence of lymph node metastasis (P = 0.011), longer postoperative hospital stay (17 days vs 15 days, P = 0.042), and not receiving adjuvant chemotherapy (P = 0.011). Relapse-free survival and cancer-specific survival were significantly shorter in the GAR ≥ 0.88 group (P = 0.007 and P = 0.023, respectively). Multivariate analyses revealed that the GAR ≥ 0.88 was independently associated with relapse-free survival [hazard ratio (HR) = 4.17, 95% confidence interval (CI) 1.32-13.14, P = 0.015)]. Moreover, CA19-9 ≥ 37 (HR = 6.56, 95% CI 2.12-20.27, p = 0.001) and not receiving adjuvant chemotherapy (HR = 4.41, 95% CI 1.28-15.26, p = 0.019) were independent poor prognostic factors for relapse-free survival.

Conclusions:

The results demonstrated that the GAR was a significant prognostic factor for OCRC patients.

High-Risk Features Are Prognostic in dMMR/MSI-H Stage II Colon Cancer

BACKGROUND

High-risk features, such as T4 disease, bowel obstruction, poorly/undifferentiated histology, lymphovascular, perineural invasion, and <12 lymph nodes sampled, indicate poor prognosis and define high-risk stage II disease in proficient mismatch repair stage II colon cancer (CC). The prognostic role of high-risk features in dMMR/MSI-H stage II CC is unknown. Similarly, the role of adjuvant therapy in high-risk stage II CC with dMMR/MSI-H (≥1 high-risk feature) has not been studied in prospective trials. The aim of this analysis of the National Cancer Database is to evaluate the prognostic value of high-risk features in stage II dMMR/MSI-H CC.

METHODS

Univariate (UVA) and multivariate (MVA) Cox proportional hazards (Cox-PH) models were built to assess the association between clinical and demographic characteristics and overall survival. Kaplan-Meier survival curves were generated with log-rank tests to evaluate the association between adjuvant chemotherapy in high-risk and low-risk cohorts separately.

RESULTS

A total of 2,293 stage II CC patients have dMMR/MSI-H; of those, 29.5% (n = 676) had high-risk features. The high-risk dMMR/MSI-H patients had worse overall survival [5-year survival and 95%CI, 73.2% (67.3-78.1%) vs. 80.3% (76.7-83.5%), p = 0.0001]. In patients with stage II dMMR/MSI-H CC, the high-risk features were associated with shorter overall survival (OS) along with male sex, positive carcinoembryonic antigen, Charlson-Deyo score >1, and older age. Adjuvant chemotherapy administration was associated with better OS, regardless of the high-risk features in dMMR/MSI-H (log-rank test, p = 0.001) or not (p = 0.0006). When stratified by age, the benefit of chemotherapy was evident only in patients age ≥65 with high-risk features.

CONCLUSION

High-risk features are prognostic in the setting of dMMR/MSI-H stage II CC. Adjuvant chemotherapy may improve survival specifically in patients ≥65 years and with high-risk features.

Combination Immunotherapies to Overcome Intrinsic Resistance to Checkpoint Blockade in Microsatellite Stable Colorectal Cancer

Although immune checkpoint inhibitors (ICIs) have shown promising results in the treatment of treating various malignancies, progress has been severely limited in metastatic colorectal cancer (mCRC). ICIs are effective in a fraction of patients with microsatellite instability-high mCRC but have little clinical efficacy in patients with microsatellite stable (MSS) mCRC, which accounts for 95% of mCRC cases. MSS mCRCs are considered to have intrinsic resistance to ICI monotherapy through multiple mechanisms. (1) They are poorly immunogenic because of their low tumor mutation burden; (2) frequent activation of the WNT/β-catenin signaling pathway excludes intratumoral CD8+ T cell immunity; (3) the tumor microenvironment is immunosuppressive because of the presence of various immunosuppressive cells, including tumor-associated macrophages and regulatory T cells; and (4) frequent liver metastasis in MSS mCRC may reduce the efficacy of ICIs. To overcome these resistance mechanisms, combination approaches using various agents, including STING agonists, MEK inhibitors, VEGF/R inhibitors, WNT/β-catenin inhibitors, oncolytic viruses, and chemo/radiotherapy, are actively ongoing. Preliminary evidence of the efficacy of some has been shown in early clinical trials. This review summarizes novel combination immunotherapy strategies described in recent preclinical and clinical studies to overcome the limitations of ICI monotherapy in MSS mCRC.

Interleukin-22 promotes PD-L1 expression via STAT3 in colon cancer cells

Blocking the expression of programmed cell death ligand 1 (PD-L1) is a promising approach for the treatment of colon cancer. The binding of PD-L1 to its receptor programmed cell death 1 (PD-1) on immune cells leads to the apoptosis of activated T cells and causes immune escape. However, there is a limited number of patients with colon cancer that can benefit from the inhibition of PD-L1, and the regulation of PD-L1 expression is poorly understood in colon cancer. The present study demonstrated that interleukin-22 (IL-22) and PD-L1 were upregulated in colon cancer tissues and there was a positive correlation between IL-22 expression and PD-L1 expression. In the present study, exogenous IL-22 was found to upregulate PD-L1 expression via the signal transducer and activator of transcription 3 signaling pathway in human colon cancer cells (DLD-1 and primary colon cancer cells). The results of the present study revealed a novel regulatory mechanism of PD-L1 expression in colon cancer, which provides a theoretical basis for decreasing the immune tolerance of colon cancer via IL-22 overexpression.