High Frequency of Coexpression of Maspin with p63 and p53 in Squamous Cell Carcinoma but Not in Adenocarcinoma of the Lung.
Bonnie Choy, Jennifer J Findeis-Hosey, Faqian Li, Loralee McMahon, Qi Yang, Haodong Xu. University of Rochester Medical Center, NY
Background: Maspin, a member of the serpin family of protease inhibitors, has been shown to inhibit tumor growth and suppress metastasis in several malignancies, including lung cancer. Previous studies have reported that p63 and p53 control maspin expression by transactivating its promoter. The aim of this study was to determine if maspin expression is correlated with p63 and p53 in squamous carcinoma and adenocarcinoma of the lung.
Design: Tissue microarrays of lung adenocarcinoma (n=161) and squamous carcinoma (n=86) were generated. Immunohistochemical studies were performed using antibodies against maspin, p63, and p53. Both nuclear and cytoplasmic staining for maspin and nuclear staining for p63 and p53 were considered positive and the percentage of positively stained cells was recorded. Concordance was considered if both maspin and p63 or p53 were expressed in the same tumor. The immunostaining intensity was graded as weak, moderate, or strong. The case with >5% of stained tumor cells was considered positive. A p value of <0.05, as determined by Fisher's exact test, was considered statistically significant.
Results: Immunohistochemical studies showed that maspin, p63 and p53 were expressed in squamous carcinomas of the lung with a majority of cases exhibiting strong positivity and the frequencies of their staining were 83/86 (96.5%) for maspin, 79/86 (91.9%) for p63 and 77/86 (89.5%) for p53. Adenocarinomas of the lung showed more variable intensity and much lower positivity for these markers than squamous carcinomas with 82/161 (50.9%) for maspin, 16/161 (9.9%) for p63 and 99/161 (61.5%) for p53. These differences were statistically significant with p<0.01 for maspin, p<0.01 for p63 and p<0.01 for p53. The frequency of concordance between maspin and p63 was 78/86 (90.7%) and 8/161 (5.0%) in squamous carcinoma and adenocarcinoma of the lung, respectively; the frequency of concordance between maspin and p53 was 75/86 (87.2%) and 62/161 (38.5%) in squamous carcinoma and adenocarcinoma of the lung, respectively. The concordance rates between maspin and p63 or p53 in squamous carcinoma and adenocarcinoma were significantly different (p<0.01).
Conclusions: Maspin, p63 and p53 are highly expressed in squamous carcinoma of the lung and expression concordance between maspin and p63 or p53 is much higher in squamous carcinoma, but not in adenocarcinoma of the lung. These findings indicate that both p63 and p53 may control maspin expression in squamous carcinoma, but not in adenocarcinoma of the lung.
Tuesday, March 1, 2011 9:30 AM
Poster Session III # 269, Tuesday Morning