P2.09-08 Correlation Between Hormone Receptor Expression and EGFR Gene Mutation in Lung Cancer Patients with Simultaneous Primary Breast Cancer

Abstract

Double primary breast cancer (BC) and lung cancer (LC) is not uncommon but research is limited. To decipher the inner pathogenesis, relationship between hormone receptor (HR) protein expression and EGFR gene mutation was explored in the present study. Clinicopathological characteristics of 400 female patients with double primary BC and LC were analyzed, while another 114 patients with single LC were compared correspondingly. Tissue samples were obtained from enrolled subjects to detect EGFR mutation status by gene sequencing analysis, and estrogen receptor (ER) and progesterone receptor (PR) expression was determined by immunohistochemistry. Among 169 patients, synchronous and metachronous double primary BC-LC cases accounted for 39.1% and 61.0%, respectively. For most female LC patients with simultaneous primary BC, adenocarcinoma was the dominant subtype (95.1%). The positivity rates were 13% for ER and 13% for PR in lung tumor tissues of 200 double BC-LC patients, slightly higher than those in single LC patients. Among BC-LC patients with mutant EGFR, 48.2% were either ER-positive (30.6%) or PR-positive (30.6%). But for those without EGFR mutation, both ER and PR could not be detected in lung tumor tissue samples. χ2 testfurther confirmed a significantly positive correlation between ER, PR expression and EGFR mutation in lung tumor tissues in double primary patients (P < 0.05). However, such relationship could not be similarly observed in single LC cases. Besides, the presence of family tumor history was associated with the onset time of the two primary cancers. Double primary BC-LC patients have distinctive clinicopathological features. Expression of HRs (both ER and PR) significantly correlated with EGFR mutation status in their lung tumor tissues.