Mucin 4 (MUC4) is a high-molecular-weight membrane-bound glycoprotein that is expressed in the foregut before epithelial differentiation. It is found in normal adult airway epithelium, non-small cell lung carcinoma (NSCLC) and in other human malignancies independent of mucus secretion. Although its tissue distribution has been studied, its utility in predicting prognosis in NSCLC is unknown.
To evaluate the relationship between MUC4 overexpression and long-term survival in patients with NSCLC.
Immunohistochemical staining for MUC4 was performed on formalin-fixed, paraffin-embedded tissue samples from 343 cases of NSCLC arranged in a high-density tissue microarray. Information about long-term survival and tumor stage was collected for all patients. Semiquantitative assessment of MUC4 staining was correlated with survival (Kaplan-Meier analysis).
MUC4 was frequently expressed in adenocarcinomas (151/187 [81%]), squamous cell carcinomas (69/ 88 [78%]), adenosquamous carcinomas (6/8 [75%]), and large cell carcinomas (33/60 [55%]). High levels of expression (combined score, 2+/3+) for MUC4 were more characteristic of adenocarcinomas (126/187 [68%]) and adenosquamous carcinomas (6/8 [75%]) than of squamous cell carcinomas (46/88 [52%]) and large cell carcinomas (17/60 [28%]) (P < .001). In patients with stage I and II adenocarcinoma, there was a trend toward longer patient survival with higher levels of MUC4 immunoreactivity compared with lower levels (P = .11).
MUC4 expression is common in pulmonary adenocarcinomas and may indicate a more favorable prognosis in early-stage adenocarcinomas.