Detection of volatile organic compounds from human prostate cancer cell using canine olfaction

Abstract Prostate cancer (PCa) is one of the most prevalent cancers of men worldwide. Currently, evaluating serum prostate-specific antigen, combined with digital rectal examination, is used as the diagnostic approach for early detection of PCa, but it has low sensitivity and difficulty in discriminating from non-malignant conditions such as prostatitis and benign prostate hyperplasia. As an alternative, a number of previous studies have reported detection of volatile organic compounds (VOCs) from biofluids of patients with PCa. However, as biofluids have several drawbacks including limited availability and lack of standardization , . Therefore, as a proof-of-concept study, VOCs from extracellular medium of PCa cell line were used in this present study. The detection of the VOCs was performed by canine olfaction as dogs have a superior olfactory system . and the purpose of this study was to evaluate whether canine olfaction can be used to detect VOCs of cancer cell line. Two dogs were trained to discriminate VOCs of the PCa cell line (PC3) from those of control groups. Tests were performed by evaluating the ability to detect VOCs of PC3 and those of PCa cell line (DU145) and bladder cancer cell line (EJ cell) for which the dogs were not trained. Sensitivity, specificity, and area under the curve (AUC) by receiver operating characteristic curve analysis were evaluated. In detecting VOCs of PC3, the AUC values of the two dogs were 0.956 and 0.976, which represented excellent detection capability. The AUC values of the DU145 were 0.892 and 0.840 and the AUC values of the EJ cell were 0.921 and 0.965. The dogs not only showed good detection ability against DU145 which originated from the same organ as PC3, but also exhibited excellent detection ability against EJ cell which originated from a different organ. In conclusion, VOCs of PCa cell line can be used to train scent-detection dogs. Further study is needed to define specific factors among VOCs that create differences between cells and to identify whether VOCs of PCa cell line can replace that of real PCa. Although further studiesareneeded to define specific factors among VOCs that create differences between cells, canine olfaction can betrained to discriminate VOCs of cancer cell from unwanted VOCs.