Expression of excision repair cross-complementation group 1 protein predicts poor outcome in patients with small cell lung cancer.
ABSTRACT Alterations in apoptosis-related proteins and DNA damage repair proteins are associated with resistance to chemotherapy or radiotherapy, which is the most important cause of treatment failure in small cell lung cancer (SCLC).
Pretreatment tumor biopsy specimens from 77 patients with SCLC (limited stage: 40, extensive stage: 37) were analyzed for p53, bcl-2, bax and ERCC1 expression by immunohistochemistry. All patients were treated with platinum-based doublets. The most commonly used regimen was etoposide/cisplatin (50 patients). In patients with limited stage SCLC, thoracic irradiation was performed either concurrently with chemotherapy or sequentially.
High expression of p53, bcl-2, bax and ERCC1 was observed in 40 (52%), 72 (94%), 38 (49%) and 13 (17%) patients, respectively. High expression of ERCC1 was associated with poor OS (1-year, 23% vs. 53%; p=0.026). When grouped according to stage, a significant correlation between high expression of ERCC1 and poor outcome was observed only in patients with limited stage SCLC (p=0.017). High expression of p53, bcl-2 and bax was not correlated with patient outcome. Multivariate analysis showed that extensive stage (p=0.006) and male gender (p=0.009) were independent predictors of poor OS, while high expression of ERCC1 failed to reach statistical significance despite a trend (p=0.057). In limited stage patients, high expression of ERCC1 was an independent prognostic factor for poor OS (p=0.046), along with male gender (p=0.033).
High expression of ERCC1 protein may be a useful predictor of poor outcome in SCLC patients treated with chemotherapy with or without radiotherapy, especially in limited stage SCLC.
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ABSTRACT: When designing molecular targeted therapeutic strategies against cancer, it is important to correlate protein expression and cell viability. However, such goal can be difficult if performed in separate assays, especially when only a fraction of cells has been efficiently transfected. Therefore, the aim of the present study was to establish a flow cytometry procedure to assess simultaneously Bcl-2 protein level and viability in small-cell lung cancer (SCLC) cells. Viability assessment was performed by staining cells with Annexin V-fluorescein isothiocyanate (FITC) and 7-aminoactinomycin D (7-AAD). Intracellular detection of Bcl-2 was carried out by immunodetection with monoclonal antibodies. Regarding viability determination, the FSC/7-AAD plot identifies the same percentage of viable cells as the FSC/Annexin V-FITC plot, although with greater sensitivity. The procedures involving cells' fixation with 1% paraformaldehyde and permeabilization with digitonin, required for intracellular Bcl-2 immunostaining did not compromise the association of 7-ADD (nor Annexin V-FITC) previously incubated with SCLC cells. It was therefore possible to simultaneously assess cell viability and Bcl-2 protein in SCLC cells. A simple, sensitive, and versatile procedure was established for the first time for the simultaneous evaluation of cell viability and intracellular detection of Bcl-2 in SCLC.Cytometry Part A 10/2008; 73A(12):1165-72. · 3.73 Impact Factor