p53 gene product expression in resected non-small cell carcinoma of the lung, with studies of concurrent cytological preparations and microwave antigen retrieval

Evaluation of apoptosis in cytologic specimens

A hallmark of neoplasia is dysregulated apoptosis, programmed cell death. Apoptosis is crucial for normal tissue homeostasis. Dysregulation of apoptotic pathways leads to reduced cytocidal responses to chemotherapeutic drugs or radiation and is a frequent contributor to therapeutic resistance in cancer. The literature pertaining to detection of apoptotic pathway constituents in cytologic specimens is reviewed herein. Virtually all methods for detecting apoptosis, including classic cytomorphologic evaluation, TUNEL assay, immunocytochemistry, and gene sequence analysis, may be applied to cytologic samples as well as tissue. Components of both intrinsic and extrinsic apoptotic pathways have been studied, including many reports examining p53 and bcl-2, as well as studies of caspase inhibitory proteins XIAP and survivin, death receptors and ligands such as Fas, Fas-ligand, and TRAIL. p53 undergoes oncogenic alteration more than any other protein; its immunocytochemical detection almost always connotes loss of its physiologic role as an inducer of apoptosis in response to a damaged genome. Several reports establish cytologic sampling as being as useful as tissue sampling. In one respect cytologic sampling is superior to tissue sampling in particular, by allowing clinicians to repeat sampling of the same tumor before and after administration of therapy; a number of reports use this approach to attempt to predict tumor response by assaying the effect of chemotherapy on the induction of apoptosis.

Immunohistochemical typing of non-small cell lung cancer on cryostat sections: correlation with clinical parameters and prognosis

AIMS

To investigate the immunohistochemical expression of a panel of biologically relevant markers in patients with non-small cell lung cancer using fresh frozen specimens and to test their prognostic relevance for identification of patients at risk.

METHODS

Seventy nine tumour infiltrated lung cancer specimens and 66 adjacent histologically tumour free tissues were analysed; 11 postmortem specimens from patients who did not suffer from a malignant disease served as a control group. Cryostat sections were stained with monoclonal antibodies against epidermal growth factor receptor (EGFR), c-erbB-2, c-erbB-3, CD82, Ki-67, p120, p53, bcl-2, and CD31.

RESULTS

At least one of the tested markers was raised above the defined cut off point in 75 of the tumours. In 55, three to six factors were increased. EGFR was raised in 32, c-erbB-2 in 29, c-erbB-3 in 46, p53 in 29, bcl-2 in 26, Ki-67 in 36, p120 in 46, and CD31 in 29. None of the tested parameters was significant in univariate survival analysis. In a second step, three variables were combined (c-erbB3, p53, and microvessel density), and cases with increased expression of two or three parameters proved to have a significantly lower survival probability than those expressing none or only one factor. In the tumour free group only 10 showed raised marker expression.

CONCLUSION

Characterisation of tumour cells in surgical specimens with immunohistological markers could help identify those patients at risk for early cancer death who could possibly profit from adjuvant treatment after curative tumour resection.