The expression of
Cathepsin B (CB) and
matrix metalloproteinase-9 (MMP-9) in extirpated tissues of
adenocarcinomas in
non-small cell lung cancer from 90 cases was investigated immunohistologically, and the correlations between the extent of the expression and the clinicopathological features were assessed for investigating the process of
tumor metastasis. It is important to reveal the mechanisms of destruction of the basal membrane and infiltration of
tumor cells at the primary lesion. Sections were obtained from 10%-
formalin-fixed and
paraffin-embedded tissues. They were reacted with an anti-human CB polyclonal antibody or an anti-human MMP-9 polyclonal antibody. Of 90 patients, 58 (64.4%) and 39 (48.3) cases were found to be positive for CB and MMP-9 expression, respectively. A significantly higher extent of the CB expression was observed in the tissues of patients who showed postoperative recurrence of the
tumor (P = 0.013). Especially, a similar observation was obtained among early cases of T1N0 (P = 0.023). In contrast, no such tendency was demonstrated in the expression profile of MMP-9. Furthermore, the
enzyme expressions were compared among different types of
metastases. Patients with higher extents of CB expression tended to show significantly higher rates of hematogenous and intrapulmonary
metastases (P = 0.023 and P = 0.010, respectively). However, there was no significant correlation between MMP-9 expression and the prognostic factor of the patients. Therefore, we suggested that evaluation of CB expression in the
tumor tissue might be useful as a postoperative prognostic factor of pulmonary
adenocarcinoma. Especially, early
cancer of T1N0 cases showing higher expression of CB may need postoperative
adjuvant chemotherapy.