title: CLCA2 as a novel immunohistochemical marker for differential diagnosis of squamous cell carcinoma from adenocarcinoma of the lung.
abstract: Recent progress in targeted therapy for lung cancer has revealed that accurate differential diagnosis between squamous cell carcinoma (SCC) and adenocarcinoma (ADC) of the lung is essential. To identify a novel immunohistochemical marker useful for differential diagnosis between the two subtypes of lung cancer, we first selected 24 SCC-specific genes and 6 ADC-specific genes using data (case number, 980) from the Cancer Genome Atlas (TCGA) database. Among the genes, we chose the CLCA2 gene, which is involved in chloride conductance and whose protein expression in lung cancer is yet to be characterized, and evaluated its protein expression status in 396 cases of primary lung cancer at Hamamatsu University Hospital. Immunohistochemical analysis revealed a significantly higher CLCA2 expression level in the SCCs than in the ADCs (P < 0.0001) and also a significantly higher frequency of CLCA2 protein expression in the SCCs (104/161, 64.6%) as compared with that in the ADCs (2/235, 0.9%) (P < 0.0001; sensitivity 64.6%, specificity 99.1%). The CLCA2 protein expression status was associated with the histological tumor grade in the SCCs. These results suggest that CLCA2 might be a novel excellent immunohistochemical marker for differentiating between primary SCC and primary ADC of the lung.
authors.affiliation: Department of Tumor Pathology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka 431-3192, Japan.
authors.forename: Kazuya
authors.identifier: 0000-0003-4963-746X
authors.initials: K
authors.lastname: Shinmura
authors.affiliation: Department of Tumor Pathology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka 431-3192, Japan.
authors.forename: Hisaki
authors.initials: H
authors.lastname: Igarashi
authors.affiliation: Department of Tumor Pathology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka 431-3192, Japan.
authors.forename: Hisami
authors.initials: H
authors.lastname: Kato
authors.affiliation: Research Equipment Center, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Kawanishi
authors.affiliation: Department of Tumor Pathology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka 431-3192, Japan ; Department of Internal Medicine 2, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Inoue
authors.affiliation: Department of Tumor Pathology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka 431-3192, Japan.
authors.forename: Satoki
authors.initials: S
authors.lastname: Nakamura
authors.affiliation: Division of Pathology, Seirei Mikatahara General Hospital, Hamamatsu 433-8558, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ogawa
authors.affiliation: Department of Surgery 1, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yamashita
authors.affiliation: Department of Surgery 1, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan.
authors.forename: Akikazu
authors.initials: A
authors.lastname: Kawase
authors.affiliation: Department of Surgery 1, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan.
authors.forename: Kazuhito
authors.initials: K
authors.lastname: Funai
authors.affiliation: Department of Tumor Pathology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka 431-3192, Japan.
authors.forename: Haruhiko
authors.identifier: 0000-0002-0779-3088
authors.initials: H
authors.lastname: Sugimura
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis* / Q000378:metabolism / Q000401:mortality; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism*; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis* / Q000378:metabolism / Q000401:mortality; D018118:Chloride Channels / Q000235:genetics / Q000378:metabolism*; D003937:Diagnosis, Differential; D005260:Female; D015870:Gene Expression; D006801:Humans; D053208:Kaplan-Meier Estimate; D008168:Lung / Q000378:metabolism; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000401:mortality; D008297:Male; D008875:Middle Aged; D046888:Tissue Array Analysis
chemical_list: D014408:Biomarkers, Tumor; C120066:CLCA2 protein, human; D018118:Chloride Channels