title: CD9 expression as a favorable prognostic marker for patients with malignant             mesothelioma.
abstract: CD9 is involved in cell growth, adhesion and motility and its expression is reported to be of prognostic significance in various types of human malignancies. We found increased cell migration in the mesothelioma cell lines MSTO-211H and TUM1 following in vitro shRNA-mediated knockdown of CD9 expression. We investigated CD9 expression in 112 malignant pleural mesotheliomas. CD9 expression was observed in 62 of 71 epithelioid, 13 of 20 biphasic and only 1 of 21 sarcomatoid mesotheliomas. Among the epithelioid mesotheliomas (EMs), CD9 expression was observed in all of the 33 cases with a differentiated type (EM-D) and in 29 of the 38 cases with a less-differentiated type (EM-LD). Patients with CD9 expression showed higher 1- and 2-year survival rates (63 and 25%) compared to the patients without CD9 expression (39 and 11%). Univariate analysis revealed that patients with CD9 expression demonstrated a more favorable survival (P=0.0025) along with other clinicopathological factors, including age younger than 60 years, IMIG stage I-II, epithelioid histology, EM-D and patients who underwent extrapleural pneumonectomy or received chemotherapy. Multivariate analysis identified CD9 expression as an independent prognostic factor with a hazard ratio (HR) of 1.99 in the analysis of all mesotheliomas (P=0.0261) and an HR of 2.60 in the analysis of EMs (P=0.0376). CD9 expression is an independent favorable prognostic marker of malignant mesothelioma.
authors.affiliation: Department of Pathology, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan. amatya@hiroshima-u.ac.jp
authors.forename: Vishwa Jeet
authors.initials: VJ
authors.lastname: Amatya
authors.forename: Yukio
authors.initials: Y
authors.lastname: Takeshima
authors.forename: Keisuke
authors.initials: K
authors.lastname: Aoe
authors.forename: Nobukazu
authors.initials: N
authors.lastname: Fujimoto
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Okamoto
authors.forename: Taketo
authors.initials: T
authors.lastname: Yamada
authors.forename: Takumi
authors.initials: T
authors.lastname: Kishimoto
authors.forename: Chikao
authors.initials: C
authors.lastname: Morimoto
authors.forename: Kouki
authors.initials: K
authors.lastname: Inai
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism*; D002448:Cell Adhesion; D002454:Cell Differentiation; D002465:Cell Movement; D049109:Cell Proliferation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008654:Mesothelioma / Q000378:metabolism / Q000401:mortality* / Q000628:therapy; D008875:Middle Aged; D009367:Neoplasm Staging; D010997:Pleural Neoplasms / Q000378:metabolism / Q000401:mortality* / Q000628:therapy; D011379:Prognosis; D034741:RNA, Small Interfering / Q000235:genetics; D015996:Survival Rate; D060245:Tetraspanin 29 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D014407:Tumor Cells, Cultured
chemical_list: D014408:Biomarkers, Tumor; C554869:CD9 protein, human; D034741:RNA, Small Interfering; D060245:Tetraspanin 29