HOTTIP levels are up-regulated in PDAC tissues and cell lines. (A) Total RNA from eight cases of pancreatic ductal adenocarcinoma (PDAC) and four cases of chronic pancreatitis were used for microarray analysis. Long noncoding RNAs (lncRNAs) upregulated >10-fold in PDAC tissues (n = 8) compared with chronic pancreatitis tissues (n = 4) are shown. (B) HOTTIP expression levels in 90 paired PDAC tissues and corresponding adjacent non-neoplastic tissues was examined via quantitative reverse transcription-polymerase chain reaction (qRT-PCR). β-actin was used as internal control. Relative gene expression was determined using the comparative delta-delta CT method, and data are presented as △△Ct. (C) HOTTIP expression was evaluated in five pancreatic cancer cell lines compared with immortalized human ductal epithelial cells by qRT-PCR. HOTTIP mRNA levels were normalized to GAPDH. Data represent the mean ± s.d. from three independent experiments. **p < 0.01, Student’s t-test.