Introduction: The aim of this study was to investigate the expression profiles of claudin (CLDN) gene family members between normal and cancerous ovaries of White Leghorn hens.

Methods: For the detection of ovarian cancer, 120-week-old White Leghorn hens (n = 40) that could not produce eggs for at least 2 months were humanely killed, and candidate cancerous ovaries were stained with hematoxylin and eosin. The existence of CLDN genes in normal and cancerous ovaries was confirmed by reverse transcription-polymerase chain reaction (RT-PCR) analysis. Quantitative real-time PCR was performed to investigate the fold change in CLDN1, CLDN5, and CLDN10 messenger RNA (mRNA) expression levels. In situ hybridization was performed to further confirm the localization of CLDN10 mRNA in normal and cancerous ovaries.

Results: In total, we obtained 3 normal and 5 cancerous ovaries from the experimental hens. Among the claudin family genes, CLDN1, CLDN5, and CLDN10 were detected in normal and/or cancerous ovaries by RT-PCR analysis. According to quantitative real-time PCR analysis, CLDN1 and CLDN5 mRNA expression levels were not significantly different between normal and cancerous ovaries, whereas the CLDN10 mRNA expression level significantly increased in cancerous ovaries compared with normal ovaries. CLDN10 mRNA was specifically detected in cancerous ovaries.

Conclusions: Our study indicates that CLDN10 is a novel biomarker for detecting ovarian cancer in the chicken. We provide new insight into using the chicken as a suitable animal model for investigating the effect and function of CLDN in human ovarian cancer.