Analyzing S100A6 expression in endoscopic ultrasonography-guided fine-needle aspiration specimens: a promising diagnostic method of pancreatic cancer.

BACKGROUND AND GOALS

Endoscopic ultrasonography-guided fine-needle aspiration (EUS-FNA) cytology in combination with other tests is necessary to improve diagnostic accuracy. We evaluated the diagnostic utility of S100A6 expression in EUS-FNA tissue samples in pancreatic ductal adenocarcinoma (PDA).

METHODS

RNA was extracted from 36 PDA and 44 nontumor pancreatic tissues obtained during surgery. S100A6 expression was quantified by real-time reverse transcription-polymerase chain reaction, and receiver operating characteristic analysis was performed to determine the cutoff value for PDA. We preoperatively performed EUS-FNA in 52 patients with pancreatic masses, then prospectively evaluated the diagnostic value of S100A6 expression of EUS-FNA samples in pancreatic cancer diagnosis. S100A6 immunohistology was conducted to validate the S100A6 expression data in PDA samples.

RESULTS

Of the 52 EUS-FNA patients with pancreatic masses, RNA was successfully extracted from 44, which comprised 34 pancreatic cancer patients and 10 patients with benign pancreatic diseases. Cytology results were malignant in 23 cases, benign in 9, and atypical or abnormal in 12. The sensitivity, specificity, and accuracy of cytology for diagnosis of pancreatic cancer were 67.65%, 100%, and 75%, respectively. When an S100A6 expression >0.005248 was defined as positive for malignancy, the sensitivity, specificity, and accuracy of S100A6 expression of EUS-FNA for diagnosis of pancreatic cancer were 88.24%, 90.00%, and 88.64%, respectively.

CONCLUSIONS

Quantification of S100A6 expression in EUS-FNA samples had a high sensitivity and specificity for the diagnosis of PDA.