S100P Expression in 449 Non-Small Cell Lung Carcinomas (NSCLCs): A Potential Diagnostic and Prognostic Marker
TC Allen, PT Cagle, LR Chirieac, S Dacic, Q Zhai. The University of Texas Health Science Center at Tyler, Tyler, TX; The Methodist Hospital, Houston, TX; Brigham and Women's Hospital and Harvard Medical School, Boston, MA; University of Pittsburg School of Medicine, Pittsburg, PA
Background: S100P, a member of the S100 family of calcium-binding proteins, is involved in cell growth and differentiation, cell cycle regulation, and metabolic control. It has been shown to be upregulated in malignant neoplasms, including lung adenocarcinoma (AD). NSCLC has an overall poor prognosis, even in surgically-resectable patients, and better diagnostic and prognostic markers are needed. We studied S100P expression in 449 NSCLCs.
Design: Tissue microarrays from three institutions containing 3 punches each of 449 NSCLCs collected over the last three decades were stained with S100P (1:100 AbKam, UK). Immunopositivity in tumor cells was graded as 0 = no staining, 1 = weak, 2 = moderate, and 3 = strong.
Results: Of the 449 cases (254 male; 195 female), 312 AD, of which 45 were bronchioloalveolar carcinomas with no or minimal invasion (AD-BAC), 80 squamous cell carcinomas (SCC), 57 large cell carcinomas (LCC)), 175 (39%) showed nuclear immunopositivity: 137/312 AD (44%); 23/80 SCC (29%); 15/57 LCC (26%). Staining showed 54 (39%) weak (34 AD, 13 SCC, 7 LCC); 36 moderate (28 AD, 4 SCC, 4 LCC); 85 strong (75 AD, 6 SCC, 4 LCC). Moderate/strong staining: 103/312 (33%) AD, 10/80 (12%) SCC, 8/57 (14%) LCC. 25/45 (55%) AD-BAC were negative/weak; 20/45 (45%) moderate/strong. Of negative/weak AD, 25/209 (12%) were AD-BAC; of moderate/strong AD, 20/85 (16% were AD-BAC.
Conclusions: AD were more likely to show moderate/strong S100P staining than other NSCLCs, and almost half of AD-BAC showed moderate/strong staining. Recent studies have shown that increased percentage of bronchioloalveolar component predicts a better prognosis in lung adenocarcinomas (Castro et al. Ann Diagn Pathol. 2001;5:274-84). S100P may potentially serve as a diagnostic and prognostic marker of AD-BAC. Further studies may help determine if S100P expression can help differentiate atypical adenomatous hyperplasia from AD-BAC.
Tuesday, March 10, 2009 1:00 PM
Poster Session IV # 229, Tuesday Afternoon