[Clinicopathological features and types of microsatellite instability in 1394 patients with colorectal cancer]

Correlation between mismatch repair statuses and the prognosis of stage I-IV colorectal cancer

Background

The role of microsatellite instability (MSI) and prognosis for stage II-III colorectal cancer (CRC) has been described, but the role of MSI in stage I and IV CRC is controversial.

Methods

A total of 2,540 CRC patients were collected from Huzhou Central Hospital, China, from January 2006 to 2016, and 783 cases were excluded. This retrospective study illustrates the correlation between MMR status and prognosis for 1,757 CRC patients as well as the correlation between MSI and prognosis for CRC patients. Two groups were classified as MSI-H and MSI-L&MSS. If the expression of one or more mismatch repair (MMR) proteins was negative, it was considered as microsatellite instability high expression (MSI-H), whereas positive expression was considered as microsatellite instability low expression and microsatellite stability (MSI-L&MSS), as assessed by correlation analyses. Overall and disease-free survival were analyzed using the Kaplan-Meier method. Univariable and multivariable analyses were conducted using Cox regression.

Results

Preoperative serum S-CEA, positive lymph, tumor size, pathologic tumor (Pt) status, node (N) stage, differentiation, chemotherapy, and the 8th Edition of the American Joint Committee on Cancer (AJCC-8) were significantly correlated with MSI (P=0.028, 0.037, 0.019, 0.007, 0.002, <0.001, <0.001, and <0.001, respectively), whereas tumor location was not associated with MSI. Univariable and multivariable analyses showed that MSI was an independent factor for CRC. The 5-year overall survival (OS) and 5-year disease-free survival (DFS, P<0.001) rates differed significantly between the two groups in stages II, III, and IV, whereas stage I did not show a significant difference (P>0.05).

Conclusion

MSI-H was associated with a good prognosis for stages II to IV, whereas stage I did not show any significant correlation. Moreover, MSI expression was an independent prognostic factor.

Expression of mismatch repair proteins, CDX-2, and p53 in colorectal adenocarcinoma and their association with clinicopathological characteristics

BACKGROUND

Microsatellite instability is caused by loss of expression of DNA mismatch repair (MMR) proteins, which are involved in one of significant pathways that lead to colorectal cancer development and progression. Both Cdx-2 and p53 play an inhibitory role in colorectal cancer and are related to some clinicopathological features.

AIM

To analyze the significance of expression of MMR proteins (MLH1, MSH2, PMS2, and MSH6), CDX-2, and p53 in colorectal adenocarcinoma.

METHODS

A total of 175 patients with colorectal adenocarcinoma who were operated at the Affiliated Hospital of Yangzhou University from January 2017 to March 2021 were selected. The expression levels of MLH1, MSH2, PMS2, MSH6, CDX-2, and p53 in colorectal cancer were detected by immunohistochemical method. The association of the expression of the above proteins with clinicopathological features of colorectal adenocarcinoma was explored by chi-square test, and Spearman rank correlation was used for correlation analysis.

RESULTS

Among 175 colorectal adenocarcinoma patients, there were 39 patients with negative expression of all four MMR proteins (22.3%). The negative expression of MSH2, MSH6, MLH1, and PMS2 was found in 12 (6.9%), 1 (0.6%), 17 (9.7%), and 28 (16.0%) cases, respectively. Among 91 colorectal adenocarcinoma patients, 34 (35.1%) had negative expression of CDX-2, and 7 (25%) had negative expression of p53 in colorectal adenocarcinoma. The negative expression of MMR proteins was significantly correlated with the age of onset, tumor site, and degree of differentiation in colorectal adenocarcinoma patients (P < 0.05), but had no significant correlation with patient gender, tumor invasion depth, or lymph node metastasis (P > 0.05). There was no correlation between the expression of MMRs protein and that of CDX-2 and p53 (P > 0.05).

CONCLUSION

The expression of MMR proteins is related to the age of onset, tumor site, and degree of differentiation. The detection of MMR proteins has important clinical significance for the early diagnosis of colorectal adenocarcinoma, the formulation of therapeutic plan, and the assessment of prognosis.