title: Clinical significance of serum claudin-1 and claudin-7 levels in patients with colorectal cancer.
abstract: The present study aimed to investigate the serum levels and clinical relevance of claudin (CLDN) 1 and CLDN7 in patients with colorectal cancer (CRC). A total of 140 patients with a pathologically confirmed diagnosis of CRC were enrolled in this study. The serum levels of CLDN1 and CLDN7 were determined using the solid-phase sandwich ELISA method. A total of 40 healthy age- and gender-matched controls were included in the analysis. The median age of the patients was 60 years (range, 24-84 years). The localization of the tumor in the majority of the patients was the colon (n=81, 58%). Of the 55 metastatic patients who received palliative chemotheraphy, 31% were chemotherapy-responsive. The baseline median serum CLDN1 and CLDN7 levels were significantly lower in non-metastatic and metastatic patients compared with those in healthy controls (CLND1, P=0.008 and 0.002; and CLND7, P=0.002 and 0.002, respectively). Moreover, known clinical variables, including poor performance status and high carcinoembryonic antigen (CEA) levels were found to be associated with lower serum CLDN1 concentrations for all patients (P=0.03 and P=0.03, respectively). High T stage and high CEA levels were found to be correlated with lower serum CLDN7 concentrations for all patients (P=0.04 and 0.03, respectively). A correlation was identified between CLDN1 and CLDN7 levels in non-metastatic and metastatic CRC patients (both P-values <0.001). Our study results did not reveal any statistical significance for serum CLDN1 or CLND7 concentrations regarding progression-free and overall survival rate. Therefore, reduced serum levels of CLDN1 and CLND7 may be useful markers in the differential diagnosis of CRC.
authors.affiliation: Clinic of General Surgery, Istanbul Bakırköy Dr Sadi Konuk Education and Research Hospital, 34156 Istanbul, Turkey.
authors.forename: Mehmet
authors.initials: M
authors.lastname: Karabulut
authors.affiliation: Clinic of General Surgery, Istanbul Bakırköy Dr Sadi Konuk Education and Research Hospital, 34156 Istanbul, Turkey.
authors.forename: Halil
authors.initials: H
authors.lastname: Alis
authors.affiliation: Clinic of General Surgery, Istanbul Bakırköy Dr Sadi Konuk Education and Research Hospital, 34156 Istanbul, Turkey.
authors.forename: Koray
authors.initials: K
authors.lastname: Bas
authors.affiliation: Department of Medical Oncology, Institute of Oncology, Istanbul University, 34093 Istanbul, Turkey.
authors.forename: Senem
authors.initials: S
authors.lastname: Karabulut
authors.affiliation: Department of Medical Oncology, Istanbul Education and Research Hospital, 34098 Istanbul, Turkey.
authors.forename: Cigdem Usul
authors.initials: CU
authors.lastname: Afsar
authors.affiliation: Department of Basic Oncology, Institute of Oncology, Istanbul University, 34390 Istanbul, Turkey.
authors.forename: Hilal
authors.initials: H
authors.lastname: Oguz
authors.affiliation: Clinic of Medical Oncology, Istanbul Bakirköy Dr Sadi Konuk Education and Research Hospital, 34156 Istanbul, Turkey.
authors.forename: Meral
authors.initials: M
authors.lastname: Gunaldi
authors.affiliation: Clinic of General Surgery, Istanbul Bakırköy Dr Sadi Konuk Education and Research Hospital, 34156 Istanbul, Turkey.
authors.forename: Cevher
authors.initials: C
authors.lastname: Akarsu
authors.affiliation: Clinic of General Surgery, Istanbul Bakırköy Dr Sadi Konuk Education and Research Hospital, 34156 Istanbul, Turkey.
authors.forename: Osman
authors.initials: O
authors.lastname: Kones
authors.affiliation: Department of Medical Oncology, Institute of Oncology, Istanbul University, 34093 Istanbul, Turkey.
authors.forename: Nuri Faruk
authors.initials: NF
authors.lastname: Aykan
keywords: claudin-1; claudin-7; colorectal cancer; low levels; serum