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Fibroadenomas (FAs) are the most common fibroepithelial lesions and the most common benign tumors of the breast in women of reproductive age. Although MED12 mutations, an overwhelming majority of all mutations, and some other gene mutations have been found in FAs, the genomic landscapes of FAs are still not completely clear and the genomic mutation spectrums of FAs in Chinese population remains unknown. Here, by performing whole exome sequencing of 12 FAs and the corresponding normal breast tissues in Chinese Han population, we observed the somatic and germline landscapes of genetic alterations. We identified 16 recurrently mutated genes with 37 nonsynonymous or frameshift somatic mutations and 27 recurrent somatic copy number variants (CNVs). In these mutated genes, MED12 was the most common in FAs, harboring 6 nonsynonymous/frameshift somatic mutations and 1 CNV. In addition, 6 germline mutations of tumor susceptibility genes in 5 FAs were identified and the tumor mutational burden of the 5 FAs was significantly higher than the other 7 FAs without germline mutations. This study provides genomic mutation spectrums of FAs in Chinese population and expand the genetic spectrum of FAs., (© 2019 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

Background: Germline mutations in the BRCA1 and BRCA2 genes greatly increase a woman's risk of developing breast and/or ovarian cancer. The prevalence and distribution of such mutations differ across races/ethnicities. Several studies have investigated Chinese women with high-risk breast cancer, but the full spectrum of the mutations in these two genes remains unclear., Methods: In this study, 133 unrelated Chinese women with familial breast/ovarian cancer living in Zhejiang, eastern China, were enrolled between the years 2008 and 2014. The complete coding regions and exon-intron boundaries of BRCA1 and BRCA2 were screened by PCR-sequencing assay. Haplotype analysis was performed to confirm BRCA1 and BRCA2 founder mutations. In silico predictions were performed to identify the non-synonymous amino acid changes that were likely to disrupt the functions of BRCA1 and BRCA2., Results: A total of 23 deleterious mutations were detected in the two genes in 31 familial breast/ovarian cancer patients with a total mutation frequency of 23.3% (31/133). The highest frequency of 50.0% (8/16) was found in breast cancer patients with a history of ovarian cancer. The frequencies of BRCA1 and BRCA2 mutations were 13.5 % (18/133) and 9.8% (13/133), respectively. We identified five novel deleterious mutations (c.3295delC, c.3780_3781delAG, c.4063_4066delAATC, c.5161 > T and c.5173insA) in BRCA1 and seven (c.1-40delGA, c.4487delC, c.469_473delAAGTC, c.5495delC, c.6141T > A, c.6359C > G and c.7588C > T) in BRCA2, which accounted for 52.2% (12/23) of the total mutations. Six recurrent mutations were found, including four (c.3780_3781delAG, c.5154G > A, c.5468-1del8 and c.5470_5477del8) in BRCA1 and two (c.3109C > T and c.5682C > G) in BRCA2. Two recurrent BRCA1 mutations (c.5154G > A and c.5468-1del8) were identified as putative founder mutations. We also found 11 unclassified variants, and nine of these are novel. The possibility was that each of the non-synonymous amino acid changes would disrupt the function of BRCA1 and BRCA2 varied according to the different algorithms used., Conclusions: BRCA1 and BRCA2 mutations accounted for a considerable proportion of hereditary breast/ovarian cancer patients from eastern China and the spectrum of the mutations of these two genes exhibited some unique features. The two BRCA1 putative founder mutations may provide a cost-effective option to screen Chinese population, while founder effects of the two mutations should be investigated in a lager sample size of patients.

Germline mutations in identified breast cancer susceptibility genes account for less than 20% of Chinese familial breast cancers. Dicer is an essential component of the microRNA-producing machinery; germline mutations of DICER1 have been confirmed in familial pleuropulmonary blastoma, ovarian sex cord-stromal tumors, and other cancers. Low expression of DICER1 is frequently detected in breast cancer. However, whether germline mutations of DICER1 occur in familial breast cancers remain unknown. Sixty-five breast cancer probands from BRCA1/BRCA2-negative Chinese breast cancer families were screened for germline mutations in DICER1. In addition, 100 unrelated healthy females were enrolled as controls. A polymerase chain reaction sequencing assay was used to screen for mutations in coding regions and at the exon-intron boundaries of DICER1. All variants in introns were evaluated using the NNSplice software to determine the potential splicing effect. A total of 12 germline variants were found, including 11 variants in introns and 1 variant in the 3'-non-coding region. Four variants (IVS8-205 C>T, IVS11+131 delGAAA, IVS16+42 delTA, and IVS19+160 T>C) were novel. Three variants (IVS11+105 C>T, IVS16+42 delTA, and 6095 T>A) may affect splice sites. None of the observed variants appeared to be disease-related, suggesting that germline mutations in DICER1 are rare or absent in familial breast cancer patients.

Objective: To understand the current status and relevant factors influencing the duration of breastfeeding in rural areas in China., Methods: Children under two years old were selected as subjects from the study on "Physical growth among the under 7-years-old children from the rural areas of ten provinces in China in 2006". Kaplan-Meier method was used to estimate the survival curves and Cox multivariate stepwise regression was used to identify the relevant factors on the duration of breastfeeding., Results: Median of the duration for breastfeeding was 12 months in rural areas of 10 provinces in China. Results of this study suggested that factors as sex, birth order, areas of residency, nationality, initiation of formula, parents' education levels, maternal services and family income were correlated with the duration of breastfeeding., Conclusion: Duration of breastfeeding among rural children under 2-years of age was short in the 10 provinces of China. Factors as level of education, residential areas and family income of the parents as well as sex of the children were correlated with the duration of breastfeeding. Intervention program should be implemented to improve the current status on breastfeeding.