Comprehensive genomic characterization of sporadic synchronous colorectal cancer: Implications for treatment optimization and clinical outcome.

Sporadic synchronous colorectal cancer (SCRC) refers to multiple primary CRC tumors detected simultaneously in an individual without predisposing hereditary conditions, which accounts for the majority of multiple CRCs while lacking a profound understanding of the genomic landscape and evolutionary dynamics to optimize its treatment. In this study, 103 primary tumor samples from 51 patients with SCRC undergo whole-exome sequencing. The germline and somatic mutations and evolutionary and clinical features are comprehensively investigated. Somatic genetic events are largely inconsistent between paired tumors. Compared with solitary CRC, SCRCs have higher prevalence of tumor mutation burden high (TMB-H; 33.3%) and microsatellite-instability high (MSI-H; 29.4%) and different mutation frequencies in oncogenic signaling pathways. Moreover, neutrally evolving SCRC tumors are associated with higher intratumoral heterogeneity and better prognosis. These findings unveil special molecular features, carcinogenesis, and prognosis of sporadic SCRC. Strategies for targeted therapy and immunotherapy should be optimized accordingly.

Comprehensive profiling of 1015 patients' exomes reveals genomic-clinical associations in colorectal cancer.

The genetic basis of colorectal cancer (CRC) and its clinical associations remain poorly understood due to limited samples or targeted genes in current studies. Here, we perform ultradeep whole-exome sequencing on 1015 patients with CRC as part of the ChangKang Project. We identify 46 high-confident significantly mutated genes, 8 of which mutate in 14.9% of patients: LYST, DAPK1, CR2, KIF16B, NPIPB15, SYTL2, ZNF91, and KIAA0586. With an unsupervised clustering algorithm, we propose a subtyping strategy that classisfies CRC patients into four genomic subtypes with distinct clinical characteristics, including hypermutated, chromosome instability with high risk, chromosome instability with low risk, and genome stability. Analysis of immunogenicity uncover the association of immunogenicity reduction with genomic subtypes and poor prognosis in CRC. Moreover, we find that mitochondrial DNA copy number is an independent factor for predicting the survival outcome of CRCs. Overall, our results provide CRC-related molecular features for clinical practice and a valuable resource for translational research.

Germline mutational profile of Chinese patients under 70 years old with colorectal cancer.

BACKGROUND: Inherited susceptibility accounts for nearly one-third of colorectal cancer (CRC) predispositions and has an 80%-100% lifetime risk of this disease. However, there are few data about germline mutations of hereditary CRC-related genes in Chinese patients with CRC. This study aimed to assess the prevalence of gene mutations related to cancer susceptibility among Chinese patients with CRC, differences between Chinese and Western patients, and the phenotype-genotype correlation. METHODS: We retrospectively collected tumor samples from 526 patients with CRC under 70 years old who underwent hereditary CRC genetic testing. A series of bioinformatic analyses, as well as statistical comparisons, were performed. RESULTS: We found that 77 patients (14.6%) harbored functional variants of the 12 genes. The mutation frequencies of the top 5 mutated genes were 6.5% for MutL homolog 1 (MLH1), 5.1% for MutS homolog 2 (MSH2), 1.0% for MSH6, 0.8% for PMS1 homolog 2 (PMS2), and 0.8% for APC regulator of the WNT signaling pathway (APC). Our data showed much higher rates of mutations of MSH6 and PMS2 genes among all mismatch repair (MMR) genes as compared with those in Western populations. Mutations in MLH1, MSH2, and MSH6 were found to be mutually exclusive. Patients with MLH1 or MSH2 mutations had higher frequencies of personal history of cancer (MLH1: 20.6% vs. 8.7%; MSH2: 25.9% vs. 8.6%) and family history of cancer than those without these mutations (MLH1: 73.5% vs. 48.4%; MSH2: 70.4% vs. 48.9%), and the lesions were more prone to occur on the right side of the colon than on the left side (MLH1: 73.5% vs. 29.3%; MSH2: 56.0% vs. 31.0%). The proportion of stage I/II disease was higher in patients with MLH1 mutations than in those without MLH1 mutations (70.6% vs. 50.7%), and the rate of polyps was higher in patients with APC mutations than in those with wild-type APC (75.0% vs. 17.4%). CONCLUSION: These results provide a full-scale landscape of hereditary susceptibility over 12 related genes in CRC patients and suggest that a comprehensive multi-gene panel testing for hereditary CRC predisposition could be a helpful analysis in clinical practice.

Trastuzumab plus docetaxel and capecitabine as a first-line treatment for HER2-positive advanced gastric or gastroesophageal junction cancer: a phase II, multicenter, open-label, single-arm study.

Gastric cancer (GC) is the second most common cancer in China. The ToGA study showed that trastuzumab in combination with fluoropyrimidine plus cisplatin prolonged overall survival (OS) in patients with human epidermal growth factor receptor 2 (HER2)-positive advanced GC (AGC). However, some patients may not be able to receive this regimen. We conducted a clinical study to evaluate the efficacy and safety of trastuzumab in combination with docetaxel+capecitabine (DX) in patients with HER2-positive AGC. This phase II, multi-center, open-label, single arm study enrolled patients with HER2-positive AGC who had not received prior treatment for metastatic disease. Patients were treated with a regimen of trastuzumab (8 mg/kg loading dose followed by 6 mg/kg, day 1), capecitabine (1000 mg/m2 twice daily, days 1-14) and docetaxel (60 mg/m2, day 1 for 6 cycles) every 3 weeks. The primary endpoint was progression-free survival (PFS) and the secondary endpoints were objective response rate (ORR), OS and safety profiles. Sixty-seven patients with AGC were enrolled from 14 centers. 64 were included in the full analysis set (FAS). The median PFS was 8.1 months (95% confidence interval [CI]: 5.6-12.8) and the median OS was 20.9 months (95% CI: 15.1-33.0). Response was evaluated in 59 patients. The ORR was 67.8%. The most common adverse events of Grade ≥3 were neutropenia, leukopenia, hand-foot syndrome, febrile neutropenia and anemia. We concluded that combination treatment with trastuzumab and DX was well-tolerated and highly effective in patients with HER2-positive AGC, and may offer an alternative to current treatments.