Surfactant Protein A Expression in Human Normal and Neoplastic Breast Epithelium

Abstract

We studied the presence of surfactant protein A (Sp-A) immunoreactivity and messenger RNA in 62 normal and abnormal breast samples. Sections were immunostained with polyclonal anti-Sp-A antibody. The association between Sp-A immunoreactivity and histologic grade of 32 invasive ductal carcinomas was assessed by 3 pathologists who scored the intensity of Sp-A immunoreactivity times the percentage of tumor immunostained; individual scores were averaged, and the final scores were correlated with tumor grade, proliferative index, and expression of estrogen and progesterone receptors. Strong Sp-A immunoreactivity was present at the luminal surface of ductal epithelial cells in normal breast samples and in benign lesions; carcinomas displayed variable immunoreactivity, inversely proportional to the degree of differentiation. Sp-A messenger RNA was detected by reverse transcriptase-polymerase chain reaction in 3 of 3 normal breast samples and 9 of 9 carcinomas. The significance of Sp-A expression in breast epithelium requires further study; possibly it has a role in native host defense or epithelial differentiation.

DMBT1 expression is down-regulated in breast cancer

“…We found that in the normal ductal epithelium Sp-A immunoreactivity is present on the luminal side, whereas in carcinomas it is present both on the luminal side as well as on the baso-lateral surfaces. In carcinomas, the Sp-A immunoreactivity is not only redistributed but also decreased as the histological tumour grade increases [20]. Remarkably, this resembles the changes of DMBT1 expression and localisation observed in other tumor types originating from mono-layered epithelia such as primary esophageal adeno-carcinomas and lung carcinomas [5,8].…”

“…It has been reported that Sp-D and Sp-A are ligands of DMBT1 products [29]. We recently demonstrated that Sp-A, in breast carcinoma tissues, has a pattern of expression resembling that of its interaction partner [20]; thus, we hypothesize that co-ordinated induction of both SP-A and DMBT1 in breast tissue may be part of a protective response as suggested by Kang et al [30] for DMBT1 and Sp-D in pulmonary epithelium.…”

Upregulation of Surfactant Protein A in Chronic Rhinosinusitis

“…6 SP-A appears to be present in other extrapulmonary sites of the body, such as in otitis media effusion products, 7 in mesentery cells, 8 and in the epithelial cells lining the gastrointestinal tract and mammary glands. 9,10 The paranasal sinus mucosa is lined by respiratory epithelium, as are the conducting airways of the lung. It has been reported that in the human, SP-A is present in the submucosal glands in the conducting airways of the lung.…”

Surfactant Protein A - From Genes to Human Lung Diseases

“…submucosal gland cells, in breast [34] and Eustachian tube epithelium [35], peritoneum, synovium [36], small and large intestine [37], colon, salivary gland, prostate, pancreas and thymus [33]. In human tissues other than lung, except for vaginal mucosa, peritoneum, synovium and Eustachian tube epithelium, only SP-A mRNA was found and no protein expression could be detected [33,38].…”