Expression of estrogen and progesterone receptors in non-small-cell lung cancer: immunohistochemical study.

Estrogen receptor (ER) and progesterone receptor (PgR) have been recognized as being involved in the tumourigenesis of non-small-cell lung cancer (NSCLC). Forty-nine resected NSCLC (39 males and 10 females) were studied immunohistochemically in formalin-fixed, paraffin-embedded sections for ER and PgR. There were 26 squamous cell carcinomas, 22 adenocarcinomas and one adenosquamous carcinoma. 38.8% (19/49)NSCLC had either a positive ER or PgR status of which one was ER+/PgR+, 2 were ER+/PgR- and 16 were ER-/PgR+. There was no statistical difference in hormone receptors status for sex and histological subtypes (p > 0.05). The immunohistochemical assay of formalin-fixed paraffin-embedded sections allows the retrospective analysis of ER and PgR in NSCLC. The ER-/PgR+ status was detected in about one third NSCLC. The discordance between these receptors is suggested to be due to either the presence of functioning variant ER or the constitutive synthesis of PgR independent of estrogen induction in certain ER-/PgR+ NSCLC.