Cytoplasmic localization of p63 is associated with poor patient survival in lung adenocarcinoma

Aims: To determine the significance of p63 protein expression in the development and progression of lung adenocarcinoma. Methods and results: The expression of p63 was immunohistochemically investigated in 92 cases of lung adenocarcinoma with a maximum diameter of 30 mm or less. p63 expression was observed not only in the nuclei (46/92 cases, 50%), but also in the cytoplasm of neoplastic cells (47/92, 51%). Nuclear localization of p63 was correlated with nuclear accumulation of p53 (P = 0.0120), whereas the presence of nuclear p63 had no apparent effect on patient survival. Cytoplasmic localization of p63 was found to be correlated with shorter survival periods by univariate and multivariate analyses (P = 0.0486 and P = 0.0488, respectively) and the relation was independent of clinicopathological factors. Cytoplasmic localization of p63 was further confirmed by immunoblots of the cytoplasmic fraction of HLC-1, a lung adenocarcinoma cell line which predominately expressed Delta Np63 alpha transcript relative to TAp63 transcript by quantitative reverse transcriptase-polymerase chain reaction. Conclusions: Cytoplasmic expression of p63 is an adverse prognostic factor in patients with adenocarcinoma of the lung.