Circulating miR-200c as a diagnostic and prognostic biomarker for gastric cancer.

BACKGROUND: MicroRNAs are aberrantly expressed and correlate with tumourigenesis and the progression of solid tumours. The miR-200 family determines the epithelial phenotype of cancer cells and regulates invasiveness and migration. Thus, we hypothesised that the quantitative detection of the miR-200 family as epithelial-specific microRNAs in the blood could be a useful clinical biomarker for gastric cancer (GC). METHODS: We initially validated the expression levels of miR-200a, 200b, 200c and 141 in GC cell lines (n = 2) and blood from healthy controls (n = 19) using real-time quantitative reverse transcription PCR (qRT-PCR). The microarray expression profiles of the miR-200 family in 160 paired samples of non-tumour gastric mucosae and GC were downloaded through ArrayExpress and analysed. MiR-200c was selected for clinical validation. The qRT-PCR prospective assessment of miR-200c was performed using 67 blood samples (52 stage I-IV GC patients and 15 controls); the area under the receiver operating characteristic curve (AUC-ROC) was estimated. The Kaplan-Meier and Breslow-Wilcoxon tests were used to assess the correlation of miR-200c with overall and progression-free survival (OS and PFS). Multivariate analyses were performed using the Cox model. RESULTS: The miR-200c blood expression levels in GC patients were significantly higher than in normal controls (p = 0.018). The AUC-ROC was 0.715 (p = 0.012). The sensitivity, specificity and accuracy rates of 65.4%, 100% and 73.1%, respectively, were observed. The levels of miR-200c in the blood above the cutoff defined by the ROC curve was found in 17.6% of stage I-II GC patients, 20.6% of stage III patients and 67.7% of stage IV patients (p < 0.001). The miR-200c expression levels were not associated with clinical or pathological characteristics or recent surgical procedures. There was a correlation (p = 0.016) with the number of lymph node metastases and the increased expression levels of miR-200c in blood were significantly associated with a poor OS (median OS, 9 vs 24 months; p = 0.016) and PFS (median PFS, 4 vs 11 months; p = 0.044). Multivariate analyses confirmed that the upregulation of miR-200c in the blood was associated with OS (HR = 2.24; p = 0.028) and PFS (HR = 2.27; p = 0.028), independent of clinical covariates. CONCLUSIONS: These data suggest that increased miR-200c levels are detected in the blood of gastric cancer patients. MiR-200c has the potential to be a predictor of progression and survival.

Expression of Wnt gene family and frizzled receptors in head and neck squamous cell carcinomas.

Genes of the Wnt and Frizzled class, expressed in HNSCC tissue and cell lines, have an established role in cell morphogenesis and differentiation, and also they have oncogenic properties. We studied Wnt and Fz genes as potential tumor-associated markers in HNSCC by qPCR. Expression levels of Wnt and Fz genes in 22 unique frozen samples from HNSCC were measured. We also assessed possible correlation between the expression levels obtained in cancer samples in relation to clinicopathologic outcome. Wnt-1 was not expressed in the majority of the HNSCC studied, whereas Wnt-5A was the most strongly expressed by the malignant tumors. Wnt-10B expression levels were related with higher grade of undifferentiation. Related to Fz genes, Fz-5 showed more expression levels in no-affectation of regional lymph nodes. Kaplan-Meier survival analyses suggest a reduced time of survival for low and high expression of Wnt-7A and Fz-5 mRNA, respectively. qPCR demonstrated that HNSCC express Wnt and Fz members, and suggested that Wnt and Fz signaling is activated in HNSCC cells.