Different TRAP220 Expression in Distinct Histologic Subtypes and Smoking Status of Lung Adenocarcinomas
MS Roh, JH Yun, CH Son, DK Yang, PJ Choi, KE Lee. Dong-A University, Busan, Korea
Background: Adenocarcinoma (ADC) is becoming the most common histologic type of lung cancer in both sex. Although most cases are seen in smokers, it develops more frequently than other histologic types in individuals who have never smoked. Recent evidence now suggests that estrogen also contributes to the pathogenesis of lung cancer. TRAP220 can serve as a binding target for transactivators involved in cell growth and development. Since TRAP 220 is also an essential coactivator that interacts directly with estrogen receptor , we examined the expression of TRAP220 protein to investigate its role in lung ADC, with particular attention paid to its different histologic subtypes and smoking history.
Design: We performed immunohistochemical detection of TRAP220 protein in eighty-three tissue samples from primary lung ADC patients using a tissue microarray and Western blotting was done to confirm the immunohistochemical observations.
Results: TRAP220 immunoreactivity was observed in 18 (21.7%) of the 83 ADC cases. Analysis of the TRAP220 expression in 6 ADC tissues and 2 normal lung tissues by Western blotting confirmed the immunohistochemical results. TRAP220 expression was higher in ADC tissues than in adjacent normal bronchial epithelial cells. TRAP220 expression was more frequently detected in acinar and papillary subtypes than in solid subtype (p =0.029). The tumors with a positive TRAP220 expression more frequently showed lymph node metastasis (p=0.037). The incidence of TRAP220 expression was significantly lower in the heavy smokers with more than 20 pack-years (p=0.047). TRAP200 expression pattern had a negative association with the number of pack-years smoked (positive expression (14.411.3 pack-years) vs. negative expression (22.215.0 pack-years)) (p=0.043).
Conclusions: This study suggests that TRAP220 might have a distinct role in the pathogenesis of acinar and papillary histologic subtypes and in non-smokers. Because ADC is a very heterogeneous subgroup of lung cancers, our data may be useful to understand the different biologic basis of the development of subtypes of lung ADC.
Tuesday, March 10, 2009 1:00 PM
Poster Session IV # 241, Tuesday Afternoon