Aims

We investigated the expression of claudins 18 and 10 in a large set of primary lung carcinomas.

Methods and results

Immunohistochemical expression of claudin 18 was seen in 12.7% and claudin 10 in 12.5% of lung carcinomas. Their expression significantly associated with each other (p< 0.001). The expression of claudin 18 and 10 was most prominent in lung adenocarcinomas which displayed positivity in 21.2% and 23.4% of cases. Female patients had more often claudin 18 and 10 positive tumors, also separately in adenocarcinomas. Interestingly, claudin 10 (p= 0.036) and claudin 18 (p= 0.001) were more common in tumours of nonsmokers. In adenocarcinomas claudin 18 predicted a better survival (p= 0.032). In Cox multivariate analysis, claudin 18 had an independent prognostic value (p= 0.027).

Conclusion

The results show that both claudins are most commonly expressed in lung adenocarcinomas and they are more occasionally detected in other histological tumour types. Curiously, female patients and non-smokers express these claudins more commonly suggesting that they may play a part in the carcinogenesis of tobacco unrelated carcinoma. Claudin 18 associated with a better survival in lung adenocarcinoma and had an independent prognostic value and may thus be used in the evaluation of patient prognosis.