Adenocarcinoma of the lung. Immunohistochemical findings (keratin/CEA)

The natural tumor suppressor protein maspin and potential application in non small cell lung cancer

The grim prognosis of lung cancer, that has an overall 10-15% survival at 5 years, remains in the US the leading cause of cancer mortality, provides a compelling rationale for studying the molecular basis of this malignancy. Surmising the common, general association with smoking, lung cancers differ at the microscopic, anatomical, epidemiological and clinical level and harbor complex genetic and epigenetic alterations. Currently, lung cancer is divided into small cell lung carcinoma (SCLC) and non small cell lung carcinoma (NSCLC) for the purpose of clinical management. (NSCLC) constitutes 80-85% of lung cancers and is further divided into histological subtypes such as adenocarcinoma, squamous cell carcinoma, and large cell carcinoma, etc. The ultimate goal for lung cancer research is to develop a strategy to block the tumor progression and improve the prognosis of lung cancer. This goal can realistically be achieved only when the biological complexity of this disease is taken into account. To this end, identification and understanding of molecular markers that are mechanistically involved in tumor progression is needed. Our recent studies suggest histological subtype-dependent distinct correlations between the expression and/or subcellular localization of tumor suppressive maspin with the progression and prognosis of NSCLC. Maspin is an epithelial specific member of the serine protease inhibitor (serpin) superfamily but recently identified as an endogenous inhibitor of histone deacetylase 1 (HDAC1). This novel biochemical activity coincides with a consensus emerged recently from the evidence that nuclear maspin confers better differentiated epithelial phenotypes, decreased tumor angiogenesis, increased tumor sensitivity to drug-induced apoptosis, and a more favorable prognosis. In the current review, we discuss the evidence that maspin may be a marker that stratifies the progression and prognosis of different subtypes of NSCLC.

Cytokeratin 20: a marker for diagnosing Merkel cell carcinoma

Merkel cell carcinoma is an aggressive cutaneous neoplasm that is often difficult to diagnose because of its histologic and immunohistochemical similarity to metastatic oat cell carcinomas and other cutaneous neoplasms. Our purpose was to determine the utility of immunoperoxidase staining of cytokeratin 20 (CK 20), a newly discovered intermediate filament protein, in Merkel cell carcinomas and other cutaneous tumors. Sixty-one tumors were sectioned and stained with antibodies directed at CK 20. The staining of Merkel cell carcinomas was compared with metastatic oat cell carcinomas, lymphomas, squamous cell carcinomas, basal cell carcinomas, melanomas, metastatic carcinoids, spiradenomas, eccrine carcinomas, adenoidcystic carcinoma, sebaceous carcinomas, hidradenomas, sebaceous epitheliomas, trichoblastomas, mixed tumors, and metastatic adenocarcinomas. Nine of 10 Merkel cell carcinomas stained with antibody to CK 20. Two metastatic carcinomas to the skin were also positive. One hidradenoma and one squamous carcinoma exhibited focal staining, but were otherwise negative. All other tumors were nonstaining. Cytokeratin 20 is a sensitive and specific marker for Merkel cell carcinoma and is helpful in distinguishing between Merkel cell carcinoma and other malignant and benign neoplasms.

Differentiation markers for lung-cancer sub-types. A comparative study of their expression in vivo and in vitro

Cell lines representing the major sub-types of lung cancer have proved to be useful tools to study the molecular and cellular biology of these malignancies, provided that they are well established and well characterized. Antibodies directed against constituents of different cellular compartments can detect the type and degree of differentiation in lung cancer and derived cell lines. Antibodies can detect cell-surface adhesion molecules, such as NCAM, cadherins and integrins. NCAM antibodies are able to differentiate between small-cell lung cancer (SCLC) and non-SCLC, both in cell lines and in tumours. In addition, a spectrum of other membrane proteins, expressed in solid tumours, such as epidermal-growth-factor receptor and carcino-embryonic antigen, are retained in cell lines. Cytoplasmic intermediate filament proteins appear to be generally retained in lung-cancer cell lines, their combinations being the same as in solid SCLC, adenocarcinomas and squamous-cell carcinomas. Nuclear expression of lamins is comparable in tumours and in their corresponding cell lines and can be used to differentiate between SCLC and non-SCLC: A-type lamins, which are present in non-SCLC, are absent in most SCLC.

Reactive lesions of the pleura. Immunohistochemical characterization

The visceral pleura of 8 lung tissue specimens with non-tumorous pleural lesions and of 10 specimens with secondary pleural infiltration of different primary tumours were tested by avidin-biotin-method with the following antibodies: anti-keratin KL1, anti-vimentin V9, anti-CEA (BMA 130c), HEA 125, Leu M1, HMFG 2 and anti-collagen type IV. In all cases anti-keratin positive subserosal cells could be proved. Activated mesothelial cells expressed vimentin additionally to keratin. The antibodies Leu M1, HEA 125 and BMA 130c (against CEA) showed no reaction in subserosal and mesothelial cells. With the antibody HMFG 2, however, a weak reaction could be observed. A distinction between reactive and neoplastic pleural lesions is not possible by using these antibodies. The antibodies LeuM1, HEA 125 and BMA 130c can be helpful for differential diagnosis in single cases with pleural carcinosis. The antibody against collagen type IV demonstrates newly developed basal membrane structures in areas with proliferating subserosal cells. Considering our results the entity of mesothelium and submesothelium is discussed with regard to the histogenetical aspect of mesothelioma.

What's new in lung tumor heterogeneity?

The categorization of lung tumors into histologically defined groups and subtypes is based on morphometric criteria, on various degrees of tumoral differentiation and growth patterns. Light microscopic examination of different sections of one and the same tumor reveals in more than 30% of the cases investigated a qualitative and quantitative heterogeneous cell and tumor growth pattern, which is further proved by additional immunohistochemical, electronmicroscopic and DNA-flow cytometry studies. According to observations on the ultrastructural level mixed or combined morphologic features signaling abnormal differentiation patterns in preneoplastic lesions of the bronchial mucosa were visible. So-called amphicrine cells containing mucous vacuoles as well as granules of neurosecretory type were found in basal cell and goblet cell hyperplasia. Squamous-type cells predominate in epidermoid metaplasia and in dysplasia. Cells containing mucous granules or tonofilaments and scant granules of dense core-type suggestive of squamous neurosecretory differentiation were present in all lesions. The ultrastructural features were correlated with the bronchial carcinoma cell heterogeneity and histogenesis.