The role of telomerase reverse transcriptase (TERT) gene promoter mutations in the aggressiveness of papillary thyroid cancer (PTC) remains to be further investigated. Here we examined the relationship of TERT promoter mutations and BRAF V600E with the clinicopathological features of PTC in 653 patients. Sanger sequencing of genomic DNA from primary PTC tumors was performed for mutation detection and genotype-clinicopathological correlation of the tumor was analyzed. BRAF V600E and TERT promoter mutations were found in 63.7% (416 of 653) and 4.1% (27 of 653) of patients, respectively; the latter became 9.8% when only tumors ≥ 1.5 cm were analyzed. TERT promoter mutations occurred more frequently in BRAF mutation-positive cases compared to wild-type cases, being 5.3% in the former versus 2.1% in the latter (P = 0.050). BRAF and TERT promoter mutations were each significantly associated with high-risk clinicopathological features of PTC, such as old patient age, large tumor size, extrathyroidal invasion, capsular invasion, and advanced disease stages. Coexistence of BRAF V600E and TERT promoter mutations was particularly associated with high-risk clinicopathological features, as exemplified by extrathyroidal invasion seen in 54.5% (12/22) of patients harboring both mutations versus 9.9% (23/232) of patients harboring neither mutation (P < 0.001). Thus, this study, the largest on TERT mutation so far, demonstrates a significant role of BRAF V600E and TERT promoter mutations in the aggressiveness of PTC, which is particularly robust and cooperative when the two mutations coexist. These results, together with previous studies, establish a significant role of these mutations in the aggressiveness of PTC.

BackgroundHuman epidermal growth factor receptor 2 (HER-2)-enriched subtype breast cancer is associated with a more aggressive phenotype and shorter survival time. Long non-coding RNAs (LncRNAs) have essential roles in tumorigenesis and occupy a central place in cancer progression. Notably, few studies have focused on the dysregulation of LncRNAs in the HER-2-enriched subtype breast cancer. In this study, we analyzed the expression profile of LncRNAs and mRNAs in this particular subtype of breast cancer.MethodsSeven pairs of HER-2-enriched subtype breast cancer and normal tissue were sequenced. We screened out differently expressed genes and measured the correlation of the expression levels of dysregulated LncRNAs and HER-2 by Pearson’s correlation coefficient analysis. Gene ontology analysis and pathway analysis were used to understand the biological roles of these differently expressed genes. Pathway act network and coexpression network were constructed.ResultsMore than 1,300 LncRNAs and 2,800 mRNAs, which were significantly differently expressed, were identified. Among these LncRNAs, AFAP1-AS1 was the most dysregulated LncRNA, while ORM2 was the most dysregulated mRNA. LOC100288637 had the highest positive correlation coefficient of 0.93 with HER-2, while RPL13P5 had the highest negative correlation coefficient of −0.87. The pathway act network showed that MAPK signaling pathway, PI3K-Akt signaling pathway, metabolic pathways, cell cycle, and regulation of actin cytoskeleton were highly related with HER-2-enriched subtype breast cancer. Coexpression network recognized LINC00636, LINC01405, ADARB2-AS1, ST8SIA6-AS1, LINC00511, and DPP10-AS1 as core genes.ConclusionThese results analyze the functions of LncRNAs and provide useful information for exploring candidate therapeutic targets and new molecular biomarkers for HER-2-enriched subtype breast cancer.

The CD44 isoform containing variant exon v6 (CD44v6) plays an important role in the progression, metastasis, and prognosis of colorectal cancer (CRC). Recently, it was found that CD44v6 is involved in acquired drug resistance. This study aimed to investigate the molecular mechanism of CD44v6 in the resistance of CRC cells to chemotherapy. A stable CD44v6 overexpression model in SW480 cells was established via lentiviral transduction. The chemosensitivity of cells to 5-fluorouracil (5-FU) and oxaliplatin (L-OHP) was determined by cell counting kit (CCK)-8, lactate dehydrogenase (LDH) release, and colony formation assays. Immunohistochemical staining of CD44v6 was performed in human CRC tissues. The key components in cell apoptosis, drug efflux and metabolism, mismatch repair, autophagy, epithelial-mesenchymal transition (EMT), and the PI3K-Akt and MAPK-Ras-Erk1/2 pathways were assessed using flow cytometry, quantitative real-time polymerase chain reaction (PCR), and western blot assays. The CD44v6 overexpression cells showed a higher viability, a lower LDH release rate, and an increased clonogenicity than the control cells under drug treatment. Moreover, overexpression of CD44v6 resulted in enhanced autophagy flux, EMT, and phosphorylation of Akt and Erk in the presence of drugs. Furthermore, high CD44v6 expression in the primary tumor was closely associated with an early recurrence in CRC patients who underwent curative surgery and adjuvant chemotherapy. In conclusion, overexpression of CD44v6 contributes to chemoresistance in SW480 cells under cytotoxic stress via the modulation of autophagy, EMT, and activation of the PI3K-Akt and MAPK-Ras-Erk pathways.

BackgroundLuminal subtype breast cancer accounts for a predominant number of breast cancers. Considering the heterogeneity of the disease, it is urgent to develop novel biomarkers to improve risk stratification and optimize therapy choices. Long non-coding RNA (lncRNA) represents an emerging and understudied class of transcripts that play a significant role in cancer biology. Growing knowledge of cancer-associated lncRNAs contributes to the development of molecular markers for prognosis evaluation and gene therapy.Materials and methodsThree pairs of primary luminal subtype breast cancer tissues and adjacent non-cancerous tissues were collected and sequenced. EBseq algorithm was used to identify differentially expressed lncRNAs. RNA sequencing data from The Cancer Genome Atlas (TCGA) database were used to validate the robustness of our RNA-seq results. Kaplan–Meier and Cox regression analyses were utilized to assess the association between the lncRNAs and overall survival of patients in TCGA cohort.ResultsA total of 796 lncRNAs were significantly dysregulated in luminal subtype breast cancer, including 436 upregulated and 360 downregulated lncRNAs. Among them, FAM83H antisense RNA 1 (FAM83H-AS1) was the most upregulated lncRNA, whereas GSN antisense RNA 1 (GSN-AS1) was the most downregulated lncRNA. Moreover, we proved that the high expression level of FAM83H-AS1 indicated unfavorable prognosis not only in luminal subtype breast cancer but also in all subtype breast cancers. To the best of our knowledge, this is the first report indicating that FAM83H-AS1 was involved in luminal subtype breast cancer and was an independent prognostic indicator.ConclusionOur study provides a rich resource to the research community for further identifying lncRNAs with diagnostic and therapeutic potentials and exploring biological function of lncRNAs in luminal subtype breast cancer.

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