Molecular subtypes in early colorectal cancer associated with clinical features and patient prognosis

Clinical and genetic drivers of oligo-metastatic disease in colon cancer

BACKGROUND

Oligo-metastatic disease (OMD) in colon cancer patients exhibits distinct clinical behavior compared to poly-metastatic disease (PMD), with a more responsive and indolent course. This study aims to identify clinical and biological factors uniquely associated with oligo-metastatic behavior.

METHODS

Metastatic colon cancer patients from an academic center underwent genetic characterization. OMD was defined as ≤3 lesions per organ, each with a total diameter <70 mm and none exceeding 25 mm. Tumor DNA sequencing by NGS utilized the TruSight Oncology 500 kit. Overall survival (OS) was determined from metastasis diagnosis until death using Kaplan-Meier analysis. Multivariate Cox regression examined prognostic links between clinicopathological and genetic factors. Associations with metastatic patterns were evaluated using Chi-square.

RESULTS

The analysis involved 104 patients (44 with OMD, 60 with PMD). OMD was more prevalent in males (P = 0.0299) and with single organ involvement (P = 0.0226). Multivariate analysis adjusted for age (>70 vs. <70 years), gender (male vs. female), tumor side (right vs. left), metastatic involvement (more than one site vs. one site), response to first-line therapy (disease control vs. no disease control), and RAS/BRAF variants (wild-type vs. mutated) identified OMD vs. PMD as the strongest independent predictor of survival (HR: 0.14; 95 % CI: 0.06-0.33; P<0.0001). OMD patients exhibited distinct molecular characteristics, including lower frequencies of BRAF p.V600E (P=0.0315) and KRAS mutations (P=0.0456), as well as a higher frequency of high tumor mutational burden (P=0.0127). Additionally, by integrating data from public datasets and our case study, we hypothesize that some gene alterations (i.e.: BRAF, SMAD4, RAF1, and mTOR) may prevent OMD occurrence.

CONCLUSION

OMD, characterized by male predominance, single-site involvement, and distinct molecular features in colon cancer, suggests the need for tailored management strategies.

Fecal biomarkers: Non-invasive diagnosis of colorectal cancer

Colorectal cancer (CRC) is the third most common cancer in the world in terms of morbidity and mortality, which brings great health hazards and economic burdens to patients and society. A fecal examination is an effective method for clinical examination and the most commonly used method for the census. It is simple, non-invasive, and suitable for large-scale population screening. With the development of molecular biology, lots of efforts have been made to discover new fecal biomarkers for the early screening of colorectal cancer. In this review, we summarize and discuss the recent advances of fecal biomarkers for CRC screening or diagnosis, including DNA biomarkers, RNA biomarkers, protein biomarkers, gut microbes and volatile organic compounds focusing on their diagnostic evaluation for CRC, which can provide a basis for the further development of new and effective CRC fecal screening and early diagnosis techniques.

Prognostic and Predictive Role of CXC Chemokine Receptor 4 in Metastatic Colorectal Cancer Patients

BACKGROUND

Colorectal cancer (CRC) is the third leading cause of cancer-related death worldwide. About 30% of patients present with metastatic disease involving predominantly the liver and a similar percentage will develop distant metastases later after removal of the primary tumor. In metastatic CRC, chemotherapies and biological drugs have prolonged survival for up to 30 months. However, there is a great need for biomarkers predictive of response and prognosis to optimize treatments. CXC chemokine receptor 4 (CXCR4) is a chemokine receptor; it binds to CXCL12 and plays a central role in colon cancer cells' growth and dissemination.

MATERIALS AND METHODS

CXCR4 was evaluated in CRC primary tissues by immunohistochemistry. Formalin-fixed, paraffin-embedded 4-μm tissue sections were immunostained using a biotin-streptavidin-peroxidase method and categorized into 2 semiquantitative classes: (i) absence of staining, ≤50% positive cells (negative/low) and (ii) >50% positive cells (high). Associations between clinic-pathologic variables and CXCR4 expression were evaluated using the χ test. The Kaplan-Meier product-limit method was applied to graph overall survival (OS). OS was defined as the time elapsed from diagnosis to death from any cause. Univariate analysis was carried out using the log-rank test. Cox proportional hazards regression was used to analyze the effect of several risk factors on OS.

RESULTS

Seventy-eight primary adenocarcinomas were analyzed; 26 were categorized as negative/low and 52 as high. Age, sex, performance status, site of metastases, KRAS mutational status, type of first-line therapy, and a number of therapy lines did not correlate with CXCR4 expression. Although not significant (P=0.0533), high CXCR4 expression was more frequently localized on the right side of the colon. Significant correlations were detected with grading (P=0.0041) and response to first-line anti-epidermal growth factor receptors agents (P<0.0001), bevacizumab (P=0.0029), and chemotherapy alone (P=0.0260). At a median follow-up of 53 months, 77 deaths have been registered. Grading [hazard ratio (HR): 1.42; confidence interval (CI): 0.89-2.28; P<0.0001], KRAS mutational status (HR: 1.73; CI: 1.03-290; P=0.0133), response to first-line chemotherapy (HR: 3.39; CI: 2.10-5.48; P<0.0001), and CXCR4 expression (HR: 3.18; CI: 2.01-5.02; P<0.0001) showed prognostic power at univariate and multivariate analyses.

CONCLUSION

In the present report, we show that CXCR4 expression on the primary tumor is an independent prognostic factor and correlates with response to first-line chemotherapy in metastatic CRC patients.

Mismatch repair status between primary colorectal tumor and metastatic tumor, a retrospective consistent study

Objectives Mismatch repair (MMR) and Microsatellite instability (MSI) are critical when considering immunotherapy and chemotherapeutic drugs an option for patients with colorectal cancer (CRC). We investigated the consistence of MMR status as well as MSI between primary CRC and metastatic tumor to see if the expression of four MMR proteins and the status of MSI are congruent in primary tumor and metastatic tumor. With the results of the study and future more relevant studies, the sites of MMR testing may be more precise for individualized treatment.

Study design Patients with clear diagnosis of sporadic CRC and distal organ metastasis were identified from a prospectively established database. The status of MMR and MSI was evaluated by immunohistochemistry (IHC) and Polymerase Chain Reaction (PCR) respectively of synchronously obtained tissue samples.

Results Forty patients with complete clinical date were enrolled. For primary tumor, 36/40 samples were tested as MMR-proficient (pMMR) and 4 were MMR-deficient (dMMR). For metastatic samples, 30 samples were tested as pMMR while 10 samples were dMMR. Six out of forty patients were tested as inconsistent status of MMR and MSI. After statistical analysis, the expression status of MMR was not statistically significant between primary and metastatic tumors (P=0.1405, larger than 0.05).

Conclusion Based on our samples, the status of MMR between primary CRC and metastatic tumor was consistent, thus test of MMR status can be performed at both sites. However, due to the limited samples enrolled in our study, the results should be interpreted carefully.

ERCC6L promotes cell growth and invasion in human colorectal cancer

Excision repair cross-complementation group 6 like (ERCC6L), a recently discovered DNA helicase, has been demonstrated to be highly expressed in a variety of human cancer types. However, the precise role of ERCC6L in colorectal cancer (CRC) remains unclear. The current study aimed to investigate the potential role of ERCC6L in the development and progression of CRC. Reverse transcription-quantitative polymerase chain reaction, western blot analysis and immunohistochemistry were used to detect the expression level of ERCC6L in 30 matched pairs of CRC and adjacent noncancerous tissues. The function of ERCC6L in cell proliferation, cycle, apoptosis, invasion and colony formation was examined in CRC cell lines. ERCC6L was revealed to be highly expressed in CRC tissues and cell lines compared with normal controls (P<0.05). The expression level of ERCC6L was significantly associated with tumor size (P<0.05), but not with other clinical features, including age, gender, differentiation and clinical stage. It was identified that reducing ERCC6L expression using small interfering RNA significantly inhibited the proliferation and colony-forming ability of CRC cell lines. Flow cytometric analysis demonstrated that ERCC6L knockdown in CRC cells inhibited cell cycle progression and increased the number of cells in the G0/G1 phase without affecting apoptosis. Furthermore, ERCC6L knockdown markedly decreased the number of invading CRC cells compared with control cells. These results suggest that ERCC6L promotes the growth and invasion of CRC cells, and ERCC6L may be a potential new target for cancer therapy.