BACKGROUNDAt present, little is known about the correlation between osteopontin (OPN) and P21 in primary non-small cell lung cancer (NSCLC). The aim of this study is to investigate the expression of OPN and P21 and their correlation in NSCLC.

METHODSThe expression of OPN and P21 was detected in 58 NSCLC tissues and 18 pulmonary inflammatory pseudotumor (PIP) as controls by immunohistochemical technique.

RESULTSThe positive rate of OPN and P21 in NSCLC was 58.6% and 70.7% respectively, which was significantly higher than those in PIP (11.1% and 16.7%) (P=0.0008, P < 0.0001). There was a positive correlation between OPN and P21 expression (P < 0.0001). Lymph node metastasis was closely related to OPN expression (P=0.0367), but not to P21 expression (P=0.4898).

CONCLUSIONSThe abnormal expression of OPN and P21 in NSCLC may act in a synergistic way. Immunopositivity of OPN may suggest a potential risk of metastasis in NSCLC.