BACKGROUND Absence of CD34-positive fibroblasts was reported within the stroma associated with invasive carcinomas. Conversely, tumor-associated desmoplastic stroma is characterized by the presence of smooth muscle actin (SMA)-reactive myofibroblasts. The present study was undertaken in order to elucidate whether the different distributions of stromal CD34-positive fibroblasts and SMA-reactive myofibroblasts are sensitive or specific markers of tumor invasion in small lung adenocarcinomas. METHODS Immunohistochemical stainings for CD34 and SMA were done in 37 peripheral adenocarcinomas less than 3.0 cm in diameter, including 16 adenocarcinomas with bronchioloalveolar carcinoma (BAC) and invasive components (mixed), and 21 invasive adenocarcinomas without BAC components (invasive). RESULTS The fibroblasts within the BAC components of the mixed group were mainly CD34-positive (81.2%) and preferentially SMA-negative (56.3%). In contrast, the fibroblasts within the invasive components of the mixed group were mainly CD34-negative (75.0%) and SMApositive (87.5%). The stromal cells of the invasive group were mostly negative for CD34 (90.5%) and positive for SMA (95.3%). CONCLUSIONS The loss of CD34 and the acquisition of SMA in the stromal cells within the tumor were related to tumor invasion (p<0.05). Thus, expression patterns of CD34 and SMA can be used to detect small foci of early stromal invasion in adenocarcinomas of the lung.
BACKGROUND CD24, also referred to as the heat stable antigen in mice, is a glycosyl phosphatidylinositol- linked glycoprotein expressed by thymocytes, B cells, neutrophils and immature neuronal cells. It has been recently observed in a variety of human malignancy. Here, we demonstrated the expression of CD24 in gastric adenocarcinomas. METHODS A total of 40 gastric adenocarcinomas and 20 tubular adenomas were immunohistochemically examined for the expression of CD24 and matrix metalloproteinase-2 (MMP-2) proteins. The immunoreactivity of CD24 was semiquantitatively scored (0, 1+, 2+) and compared with clinicopathologic variables and MMP-2 expression in tumor cells. RESULTS CD24 was rarely expressed in normal gastric tissue and not expressed in tubular adenoma. In contrast, a moderate/strong expression (2+) of CD24 was observed in 25% of gastric adenocarcinomas, and 30% cases showed a weak CD24 staining (1+). Moreover, CD24 expression was significantly correlated with the depth of tumor invasion and MMP-2 expression. CONCLUSION These results suggest that the aberrant expression of CD24 in gastric adenocarcinomas might be associated with tumor progression and invasiveness.