Objective: To investigate the differences in molecular classification of endometrial carcinoma (EC) between various technical methods and to explore molecular classification schemes suitable for Chinese population. Methods: The study used a comprehensive scheme of next generation sequencing (NGS) and immunohistochemistry for molecular classification of 254 EC cases that were obtained at Department of Pathology, Obstetrics and Gynecology Hospital of Fudan University, Shanghai, China from April 2021 to March 2022. According to the recommended threshold of Sanger sequencing which was approximate-20% variant allele fraction (VAF), NGS data were extracted to simulate the results of Sanger sequencing. Results: The 254 EC patients had a mean age of 51 years (range, 24 to 89 years). Combination of POLE (9-14 exons), TP53 total exons and microsatellite instability (MSI) detection was a better single scheme than NGS alone, while combination of MSI fragment analysis and conventional immunohistochemistry was the best solution and seemed best aligned with TCGA data and recent studies. POLE ultramuted type, mismatch repair defect type, TP53 mutant type and non-specific molecular characteristic type accounted for 11.4% (29/254), 31.5% (80/254), 22.4% (57/254) and 34.6% (88/254) of the cases, respectively. If Sanger sequencing was adopted for POLE and TP53 detection, the frequencies of these EC types were 9.1% (23/254), 31.5% (80/254), 12.9% (33/254) and 46.6% (118/254), respectively, with greatly increasing non-specific molecular characteristics cases. If POLE was detected by Sanger sequencing and others by immunohistochemistry, they were 9.1% (23/254), 42.2% (92/218), 13.8% (35/254) and 40.9% (105/254), respectively, with increasing the false positive rates of the mismatch repair defect group. Conclusions: Small and medium-sized NGS panels with MSI detection is a better solution than NGS alone. Sanger sequencing is currently available for POLE mutation detection, which is not sensitive enough for TP53 mutation detection, and seems equivalent to the efficiency of TP53 by immunohistochemistry. Further optimization of small and medium-sized NGS panels covering MSI detection and POLE and TP53 full exons may be the best choice for the future to meet national conditions.
Female ; Humans ; Middle Aged ; China ; Endometrial Neoplasms/pathology* ; Exons ; High-Throughput Nucleotide Sequencing ; Immunohistochemistry ; Microsatellite Instability ; Mutation ; Young Adult ; Adult ; Aged ; Aged, 80 and over

OBJECTIVE: To analyze the differences and characteristics of microsatellite instability (MSI) in endometrial cancer (EMC), by using colorectal cancer (CRC) as control. METHODS: In the study, 228 cases of EMC were collected. For comparative analysis, 770 cases of CRC were collected. Mismatch repair (MMR) expression was detected by immunohistochemistry (IHC), and microsatellite instability (MSI) was analyzed by PCR and capillary electrophoresis fragment analysis (MSI-PCR). MSI-PCR was detected using five mononucleotide repeat markers: BAT-25, BAT-26, NR-21, NR-24, and MONO-27. RESULTS: In EMC, we found 27.19% (62/228) of deficient mismatch repair (dMMR) using IHC, significantly higher than CRC (7.79%, 60/770). Meanwhile, subclonal expression of MMR protein was found in 4 cases of dMMR-EMC and 2 cases of dMMR-CRC. According to the criteria of major micro-satellite shift, we found 16.23% (37/228) of MSI-high (MSI-H), 2.63% (6/228) of MSI-low (MSI-L), and 81.14% (185/228) of microsatellite stability (MSS) in EMC using MSI-PCR. The discor-dance rate between MMR-IHC and MSI-PCR in EMC was 11.84% (27/228). In CRC, we found 8.05% (62/770) of MSI-H, 0.13% (1/770) of MSI-L, and 91.82% (707/770) of MSS. The discordance rate between MMR-IHC and MSI-PCR in CRC was only 0.52% (4/770). However, according to the criteria of minimal microsatellite shift, 12 cases of EMC showed minimal microsatellite shift including 8 cases of dMMR/MSS and 4 cases of dMMR/MSI-L and these cases were ultimately evaluated as dMMR/MSI-H. Then, 21.49% (49/228) of EMC showed MSI-H and the discordance rate MMR-IHC and MSI-PCR in EMC decreased to 6.58% (15/228). No minimal microsatellite shift was found in CRC. Compared with EMC group with major microsatellite shift, cases with minimal microsatellite shift showed younger age, better tumor differentiation, and earlier International Federation of Gynecology and Obstetrics (FIGO) stage. There were significant differences in histological variant and FIGO stage between the two groups (P < 0.001, P=0.006). CONCLUSION EMC was more prone to minimal microsatellite shift, which should not be ignored in the interpretation of MSI-PCR results. The combined detection of MMR-IHC and MSI-PCR is the most sensitive and specific method to capture MSI tumors.
Female ; Humans ; Microsatellite Instability ; Colorectal Neoplasms ; Microsatellite Repeats ; Endometrial Neoplasms ; DNA Mismatch Repair

OBJECTIVE: To investigate the correlation of stress-inducible phosphoprotein 1 (STIP1) expression level with prognosis of different cancers and its potential role in immunotherapy. METHODS: TCGA, TARGET and GTEx databases were used for bioinformatic analysis of STIP1 expression level and its prognostic value in different cancers. We also detected STIP1 expression immunohistochemically in 10 pairs of colorectal cancer and adjacent tissues. We further analyzed the correlation of STIP1 expression level with tumor mutational burden, microsatellite instability, immune cell infiltration, immune regulators and outcomes of different cancers. STIP1- related proteins were identified using protein- protein interaction (PPI) network analysis, and functional enrichment analysis was performed to analyze the regulatory pathways involving STIP1. RESULTS: Bioinformatics analysis showed that STIP1 was highly expressed in most tumors compared with the normal tissues (P < 0.05), which was confirmed by immunohistochemistry of the 10 pairs of colorectal cancer tissues. STIP1 expression level was correlated with clinical stages of multiple cancers (P < 0.05), and in some cancer types, an upregulated STIP1 expression was correlated with a poor prognosis of the patients in terms of overall survival, disease-specific survival, disease-free survival and progression-free survival (P < 0.05). STIP1 expression was significantly correlated with tumor mutational burden, microsatellite instability, immune cell infiltration and immunomodulatory factors in most tumors (P < 0.05). PPI network analysis indicated that STIP1-related proteins included HSPA4, HSPA8, and HSP90AA1. KEGG enrichment analysis suggested that the high expression of STIP1 in liver cancer was related mainly with valerate metabolism, tryptophan metabolism, and butyrate metabolism pathways; HALLMARK enrichment analysis suggested high STIP1 expression in liver cancer was involved in bile acid and fatty acid metabolism. CONCLUSION STIP1 is up-regulated in multiple cancer types and its expression level is correlated with clinical tumor stage, tumor mutational burden, microsatellite instability, immune cell infiltration and immunomodulatory factors.
Humans ; Microsatellite Instability ; Liver Neoplasms ; Immunotherapy ; Prognosis ; Computational Biology ; Heat-Shock Proteins ; Colorectal Neoplasms

Immunotherapy has been one of the hot topics in the field of colorectal cancer research in recent years. Patients with microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR) are the main beneficiaries of immunotherapy. The response rate of patients with dMMR/MSI-H colorectal cancer receiving neoadjuvant immunotherapy is nearly 100%, of which the pathological complete response rate approximately accounts for 60%-67%. The prospect of neoadjuvant immunotherapy in dMMR or MSI-H colorectal cancer patients, especially in the rectal cancer patients, lies in achieving sustainable clinical complete response so as to achieve organ preservation and avoid adverse effects on reproductive, sexual, bowel and bladder function after surgery and radiotherapy. Studies have shown that part of the colorectal cancer patients of microsatellite stability (MSS) or mismatch repair proficient (pMMR) can respond to neoadjuvant immunotherapy in combination with other treatment methods such as radiotherapy and chemotherapy. In pMMR or MSS colorectal cancer, optimizing neoadjuvant immunotherapy regimens and finding effective efficacy prediction biomarkers are important research directions. In neoadjuvant immunotherapy, overcoming primary and secondary resistance and identifying the pseudoprogression and hyperprogression of neoadjuvant immunotherapy are clinical challenges that require attention. This paper comprehensively reviews the research progress, controversies,challenges and future research directions of neoadjuvant immunotherapy (mainly immune checkpoint inhibitors) in colorectal cancer.
Humans ; Neoadjuvant Therapy/methods* ; Colorectal Neoplasms/drug therapy* ; Colonic Neoplasms/pathology* ; Immunotherapy/methods* ; DNA Mismatch Repair ; Microsatellite Instability

Objective: To explore the concordance and causes of different mismatch repair (MMR) and microsatellite instability (MSI) detection results in endometrial carcinoma (EC) molecular typing. Methods: A total of 214 EC patients diagnosed from January 2021 to April 2023 were selected at the Department of Pathology, Peking University Third Hospital. The immunohistochemistry (IHC) results of MMR protein were reviewed. Tumor specific somatic mutations, MMR germline mutations, microsatellite scores and tumor mutation burden (TMB) were detected by next-generation sequencing (NGS) with multi-gene panel. Methylation-specific PCR was used to detect the methylation status of MLH1 gene promoter in cases with deficient MLH1 protein expression. In cases with discrepant results between MMR-IHC and MSI-NGS, the MSI status was detected again by PCR (MSI-PCR), and the molecular typing was determined by combining the results of TMB and MLH1 gene promoter methylation. Results: (1) In this study, there were 22 cases of POLE gene mutation subtype, 55 cases of mismatch repair deficient (MMR-d) subtype, 29 cases of p53 abnormal subtype, and 108 cases of no specific molecular profile (NSMP). The median age at diagnosis of MMR-d subtype (54 years old) and the proportion of aggressive histological types (40.0%, 22/55) were higher than those of NSMP subtype [50 years old and 12.0% (13/108) respectively; all P<0.05]. (2) Among 214 patients, MMR-IHC test showed that 153 patients were mismatch repair proficient (MMR-p), 49 patients were MMR-d, and 12 patients were difficult to evaluate directly. MSI-NGS showed that 164 patients were microsatellite stable (MSS; equal to MMR-p), 48 patients were high microsatellite instability (MSI-H; equal to MMR-d), and 2 patients had no MSI-NGS results because the effective sequencing depth did not meet the quality control. The overall concordance between MMR-IHC and MSI-NGS was 94.3% (200/212). All the 12 discrepant cases were MMR-d or subclonal loss of MMR protein by IHC, but MSS by NGS. Among them, 10 cases were loss or subclonal loss of MLH1 and (or) PMS2 protein. Three discrepant cases were classified as POLE gene mutation subtype. In the remaining 9 cases, 5 cases and 3 cases were confirmed as MSI-H and low microsatellite instability (MSI-L) respectively by MSI-PCR, 6 cases were detected as MLH1 gene promoter methylation and 7 cases demonstrated high TMB (>10 mutations/Mb). These 9 cases were classified as MMR-d EC. (3) Lynch syndrome was diagnosed in 27.3% (15/55) of all 55 MMR-d EC cases, and the TMB of EC with MSH2 and (or) MSH6 protein loss or associated with Lynch syndrome [(71.0±26.2) and (71.5±20.1) mutations/Mb respectively] were significantly higher than those of EC with MLH1 and (or) PMS2 loss or sporadic MMR-d EC [(38.2±19.1) and (41.9±24.3) mutations/Mb respectively, all P<0.01]. The top 10 most frequently mutated genes in MMR-d EC were PTEN (85.5%, 47/55), ARID1A (80.0%, 44/55), PIK3CA (69.1%, 38/55), KMT2B (60.0%, 33/55), CTCF (45.5%, 25/55), RNF43 (40.0%, 22/55), KRAS (36.4%, 20/55), CREBBP (34.5%, 19/55), LRP1B (32.7%, 18/55) and BRCA2 (32.7%, 18/55). Concurrent PTEN, ARID1A and PIK3CA gene mutations were found in 50.9% (28/55) of MMR-d EC patients. Conclusions: The concordance of MMR-IHC and MSI-NGS in EC is relatively high.The discordance in a few MMR-d EC are mostly found in cases with MLH1 and (or) PMS2 protein loss or MMR protein subclonal staining caused by MLH1 gene promoter hypermethylation. In order to provide accurate molecular typing for EC patients, MLH1 gene methylation, MSI-PCR, MMR gene germline mutation and TMB should be combined to comprehensively evaluate MMR and MSI status.
Female ; Humans ; Middle Aged ; Class I Phosphatidylinositol 3-Kinases/metabolism* ; Colorectal Neoplasms, Hereditary Nonpolyposis/diagnosis* ; DNA Mismatch Repair/genetics* ; Endometrial Neoplasms/pathology* ; Microsatellite Instability ; Mismatch Repair Endonuclease PMS2/genetics* ; Molecular Typing

BACKGROUND: Microsatellite instability (MSI) is a key biomarker for cancer immunotherapy and prognosis. Integration of MSI testing into a next-generation-sequencing (NGS) panel could save tissue sample, reduce turn-around time and cost, and provide MSI status and comprehensive genomic profiling in single test. We aimed to develop an MSI calling model to detect MSI status along with the NGS panel-based profiling test using tumor-only samples. METHODS: From January 2019 to December 2020, a total of 174 colorectal cancer (CRC) patients were enrolled, including 31 MSI-high (MSI-H) and 143 microsatellite stability (MSS) cases. Among them, 56 paired tumor and normal samples (10 MSI-H and 46 MSS) were used for modeling, and another 118 tumor-only samples were used for validation. MSI polymerase chain reaction (MSI-PCR) was performed as the gold standard. A baseline was built for the selected microsatellite loci using the NGS data of 56 normal blood samples. An MSI detection model was constructed by analyzing the NGS data of tissue samples. The performance of the model was compared with the results of MSI-PCR. RESULTS: We first intersected the target genomic regions of the NGS panels used in this study to select common microsatellite loci. A total of 42 loci including 23 mononucleotide repeat sites and 19 longer repeat sites were candidates for modeling. As mononucleotide repeat sites are more sensitive and specific for detecting MSI status than sites with longer length motif and the mononucleotide repeat sites performed even better than the total sites, a model containing 23 mononucleotide repeat sites was constructed and named Colorectal Cancer Microsatellite Instability test (CRC-MSI). The model achieved 100% sensitivity and 100% specificity when compared with MSI-PCR in both training and validation sets. Furthermore, the CRC-MSI model was robust with the tumor content as low as 6%. In addition, 8 out of 10 MSI-H samples showed alternations in the four mismatch repair genes ( MLH1 , MSH2 , MSH6 , and PMS2 ). CONCLUSION MSI status can be accurately determined along the targeted NGS panels using only tumor samples. The performance of mononucleotide repeat sites surpasses loci with longer repeat motif in MSI calling.
Humans ; Microsatellite Instability ; Colorectal Neoplasms/diagnosis* ; Microsatellite Repeats/genetics* ; DNA Mismatch Repair

Humans ; Small Cell Lung Carcinoma/drug therapy* ; Lung Neoplasms/drug therapy* ; Colonic Neoplasms/drug therapy* ; Microsatellite Instability ; DNA Mismatch Repair ; Colorectal Neoplasms

Humans ; Small Cell Lung Carcinoma/drug therapy* ; Lung Neoplasms/drug therapy* ; Colonic Neoplasms/drug therapy* ; Microsatellite Instability ; DNA Mismatch Repair ; Colorectal Neoplasms

Microsatellite instability-high (MSI-H) colorectal cancer accounts for approximately 10%-15% of all colorectal cancer patients, while in metastatic diseases the MSI-H population accounts for only 5% of patients. Previous studies have shown that early-stage MSI-H colorectal cancer patients have a good prognosis, but those with advanced disease have a poor prognosis and are not sensitive to chemotherapy. The advent of PD-1 antibodies has significantly improved the prognosis and changed treatment landscape in this population, not only achieving good outcomes in late-line therapy, but also significantly outperforming traditional chemotherapy combined with targeted therapy in first-line therapy. How to overcome primary and secondary drug resistance is a key issue in improving the outcome of MSI-H metastatic colorectal cancer, and commonly used approaches include changing chemotherapy regimens, combining with other immunotherapies, combining with anti-angiogenesis, and local treatments (surgery, radiotherapy, or interventional therapy). It is worth noting that immunotherapy has certain lifelong or even lethal toxicity, and the indications for neoadjuvant immunotherapy must be evaluated with caution. Neoadjuvant immunotherapy in MSI-H advantaged population can achieve high rates of pathological complete remission (pCR) and clinical complete remission (cCR). Therefore, for MSI-H patients with a strong intention to preserve anal sphincter and a strict evaluation of cCR after neoadjuvant immunotherapy, the Watch-and-Wait strategy offers an opportunity to preserve sphincter function and improve long-term survival quality in a subset of mid-to-low rectal cancers. Research on adjuvant immunotherapy in the field of colorectal cancer is also in full swing, and the results are worth waiting for.
Colonic Neoplasms ; Colorectal Neoplasms/therapy* ; Humans ; Immunotherapy/methods* ; Microsatellite Instability ; Microsatellite Repeats

OBJECTIVE: To assess the association of genomic instability of epithelial cadherin 1 (CDH1) gene and clinicopathological characteristics of gastric cancer. METHODS: In total 120 paraffin-embedded gastric cancer tissue specimen were prepared, and genomic DNA was extracted. The genomic instability of the CDH1 gene was analyzed by immunohistochemistry and silver staining PCR-single-strand conformation polymorphism. RESULTS: The number of information individuals (heterozygotes) was 98 for the D16S752 locus. The detection rates for microsatellite instability (MSI) and loss of heterozygosity (LOH) at the D16S752 locus and the positive rate of CDH1 protein were 19.39%, 16.33% and 51.02%, respectively. The detection rate of MSI in TNM stages I or II was significantly higher than that in stages III or IV (P<0.05) while the detection rate of LOH was significantly lower than that in stages III or IV (P<0.05). The positive rate of CDH1 protein in TNM stages III or IV was significantly lower than that in stages I or II (P<0.05). The detection rate of MSI of cases with lymph node metastasis was significantly lower than that of without lymph node metastasis (P<0.05) while the detection rate of LOH was significantly higher than that without lymph node metastasis (P<0.05). The positive rate of CDH1 protein in patients with lymph node metastasis was significantly lower than that in patients without lymph node metastasis (P<0.05). The positive rate of CDH1 protein in MSI-positive group was significantly higher than that in MSI-negative group (P<0.05), and the positive rate of CDH1 protein in the LOH-positive group was significantly lower than that the LOH-negative group (P<0.05). CONCLUSION The genomic instability of the CDH1 gene is associated with the progression of gastric cancer. MSI at the D16S752 locus may be used as a molecular marker for early gastric cancer, while LOH at this locus mostly occurs in advanced gastric cancer and can be regarded as an effective indicators for malignancy evaluation and prognosis.
Humans ; Stomach Neoplasms/pathology* ; Lymphatic Metastasis ; Cdh1 Proteins/genetics* ; Microsatellite Instability ; Loss of Heterozygosity ; Genomic Instability ; Microsatellite Repeats ; Antigens, CD/genetics* ; Cadherins/genetics*