Background: To study the expressing features and significance of extracellular matrix(ECM)-laminin(LN),collagen IV(Coll IV),fibronectin(FN) and cell adhesion molecule(A-CAM) in the three subtypes of the bronchiolo-alveolar carcinoma(BAC) and conventional pulmonary adenocarcinoma(CPA).
Methods: Using immunohistochemical LSAB technique,the distribution and expression of ECM and A-CAM were examined in 50 cases of BAC(including 14 mucinous,22 nonmucinous and 14 sclerosing) and 6 of CPA.
Results: LN,Coll IV and FN in the basement membrane were stained as uninterrupted narrow line in the mucinous BAC and the pulmonary parenchyma adjacent to the carcinoma. In the nonmucinous BAC,ECM showed as irregular tram-track like double layers. The peripheral areas of the sclerosing BAC was virtually identical in staining pattern to the nonmucinous,and the central areas,which showed disrupted or absent in the basement membrane surrounding the glands embedded in the fibrous stroma,was similar to that of CPA. The frequency of A-CAM expression in BAC and CPA was 60%(30/50) and 83% (5/6) respectively, with no significant correlation found(P>0.05). The percentage of A-CAM in three BAC subtypes was 43%(6/14),55%(12/22) and 86%(12/14),which appeared as increased tendency. There was a significant difference between the mucinous and sclerosing BAC(P<0.05),while the sclerosing BAC was close to CPA.
Conclusions: On the basis of the distribution and expression of ECM and A-CAM,BAC should be taken as a subtype of CPA. The mucinous BAC may be a real BAC. Perhaps there is some differentiation correlation among three subtypes of BAC and CPA.