EXPRESSION OF MATRIX METALLOPROTEINASE (GELATINASE) IN T1 ADENOCARCINOMA OF THE LUNG

The expression of matrix metalloproteinase-2 (MMP-2; 72 kDa type IV co llagenase/gelatinase A) and MMP-9 (92 kDa type IV collagenase/gelatina se B) was immunohistochemically investigated in 79 T1 adenocarcinomas of the lung using non-commercial polyclonal anti-MMP-2 and -9 antibodi es. Thirty-two (41%) and 22 (28%) among the 79 cases were positive in the tumor cells for MMP-2 and -9, respectively. The incidences of MMP- 2 and -9 immunoreactivities were higher (64 and 45%, respectively) in poorly differentiated tumors than in well differentiated tumors (36 an d 25%, respectively), and lower in bronchioloalveolar carcinoma (22 an d 10%, respectively) compared with other subtypes of adenocarcinoma. T he prognosis for patients with MMP-2 and/or -9 positive immunoreactivi ties was significantly poorer than for those with a MMP-negative tumor (P<0.05). The degree of collagenization was divided into four grades, and tumors with a small to abundant amount of collagen (grade 2 and g rade 3 fibrosis) had a higher incidence of immunoreactivity to both ty pes of MMP. It is estimated that these expressions might be responsibl e for tumor invasion, metastasis, and for grade 2 and grade 3 fibrosis in T1 adenocarcinoma of the lung.