BACKGROUND: Loss of growth inhibitory response to transforming growth factor-b (TGF-b) is a common feature of epithelial cancers. Recent studies have reported that genetic lesions and overexpression of oncoproteins in TGF-b/Smads signalling cascade contribute to the TGF-b resistance. Here, we showed that the overexpressed FOXG1 was involved in attenuating the anti-proliferative control of TGF-b/Smads signalling in ovarian cancer. METHODS: FOXG1 and p21 WAF1/CIP1 expressions were evaluated by real-time quantitative reverse-transcription polymerase chain reaction (RT -PCR), western blot and immunohistochemical analyses. The effect of FOXG1 on p21 WAF1/CIP1 transcriptional activity was examined by luciferase reporter assays. Cell lines stably expressing or short hairpin RNA interference-mediated knockdown FOXG1 were established for studying the gain-or-loss functional effects of FOXG1. XTT cell proliferation assay was used to measure cell growth of ovarian cancer cells. RESULTS: Quantitative RT -PCR and western blot analyses showed that FOXG1 was upregulated and inversely associated with the expression levels of p21 WAF1/CIP1 in ovarian cancer. The overexpression of FOXG1 was significantly correlated with high-grade ovarian cancer (P ¼ 0.025). Immunohistochemical analysis on ovarian cancer tissue array was further evidenced that FOXG1 was highly expressed and significantly correlated with high-grade ovarian cancer (P ¼ 0.048). Functionally, enforced expression of FOXG1 selectively blocked the TGF-b-induced p21 WAF1/CIP1 expressions and increased cell proliferation in ovarian cancer cells. Conversely, FOXG1 knockdown resulted in a 20 -26% decrease in cell proliferation together with 16 -33% increase in p21 WAF1/CIP1 expression. Notably, FOXG1 was able to inhibit the p21 WAF1/CIP1 promoter activity in a p53-independent manner by transient reporter assays.

Mutation in BRCA1/BRCA2 genes accounts for 20% of familial breast cancers, 5% to 10% of which may be due to other less penetrant genes which are still incompletely studied. Herein, a four-gene panel was used to examine the prevalence of BRCA1, BRCA2, TP53, and PTEN in hereditary breast and ovarian cancers in Southern Chinese population. In this cohort, 948 high-risk breast and/or ovarian patients were recruited for genetic screening by next-generation sequencing (NGS). The performance of our NGS pipeline was evaluated with 80 Sanger-validated known mutations and eight negative cases. With appropriate bioinformatics analysis pipeline, the detection sensitivity of NGS is comparable with Sanger sequencing. The prevalence of BRCA1/BRCA2 germline mutations was 9.4% in our Chinese cohort, of which 48.8% of the mutations arose from hotspot mutations. With the use of a tailor-made algorithm, HomopolymerQZ, more mutations were detected compared with single mutation detection algorithm. The frequencies of PTEN and TP53 were 0.21% and 0.53%, respectively, in the Southern Chinese patients with breast and/or ovarian cancers. High-throughput NGS approach allows the incorporation of control cohort that provides an ethnicity-specific data for polymorphic variants. Our data suggest that hotspot mutations screening such as SNaPshot could be an effective preliminary screening alternative adopted in a standard clinical laboratory without NGS setup.

Activating mutations of the epidermal growth factor receptor (EGFR) gene in non-small cell lung cancer predict for a favorable clinical response to tyrosine kinase inhibitor therapy. Although Sanger sequencing is a conventional method to detect EGFR gene mutations, multiplex real-time allele-specific polymerase chain reaction (PCR) systems are increasingly used in the routine molecular diagnostic setting. We aim to evaluate 2 proprietary real-time PCR assays (cobas and therascreen) against Sanger sequencing in the detection of EGFR gene mutations. The overall concordance rate between cobas and therascreen assays with Sanger sequencing was 89% and 88%, respectively, and increased to 96% and 98%, respectively, if the mutations not covered were excluded. The cobas assay showed a superior coverage of exon 20 mutations, but L861Q was not targeted. The nature of specimen, DNA integrity, and tumor cell content are factors that affect the assay performance. DNA extracted from cell block and clot of pleural fluid gave rise to 1 invalid call and 1 false-negative result by the cobas assay and 1 missed T790M mutation and 1 false-negative result by the therascreen assay. Both assays are around 5 times more expensive compared with Sanger sequencing in terms of reagent cost. We conclude that both assays prove to be a rapid, simple, and validated method in detecting the most common and clinically significant EGFR gene mutations in non-small cell lung cancer. Although less convenient compared with real-time PCR assays, Sanger sequencing is cheaper in terms of reagent cost and allows the detection of rare or novel EGFR gene mutations.