Prognostic implications of calbindin-D28k expression in lung cancer: analysis of 452 cases

Calbindin D28k (Ca-D28k) acts as a buffering system to maintain cellular calcium homeostasis and is thought to play a role in inhibiting apoptosis. The goals of this study were to assess CA-D28k expression in lung carcinomas and to correlate these results with patient survival. A total of 452 lung carcinomas were immunostained with a monoclonal antibody specific for Ca-D28K using an avidin-biotin peroxidase technique. The number of cells with nuclear staining was graded semiquantitatively into one of five groups: 0, fewer than 10%, 10 to 25%, more than 25 to 50%, more than 50 to 75%, and more than 75%. Results were correlated with patient survival using Kaplan-Meier survival curves. A total of 335 of 452 (74%) lung carcinomas were positive for Ca-D28k. There was no statistically significant difference in the prevalence of Ca-D28k expression in tumors of different histologic type. Kaplan-Meier survival analysis revealed that for patients with adenocarcinoma, those with Ca-D28k-positive tumors had a better overall survival than patients with Ca-D28k-negative tumors (P = .036). This difference was also significant for patients with Stages I and II adenocarcinomas (P = .033). No statistically significant difference in prognosis was observed for patients with Stages III and IV adenocarcinomas or for patients with other lung carcinoma types of varying stage. Ca-D28k is commonly expressed in lung carcinomas of all histologic types. For patients with localized adenocarcinoma of the lung, Ca-D28k expression correlated with improved survival. No correlation between Ca-D28k expression and patient survival was found for disseminated adenocarcinoma and for other histologic types of lung carcinoma.