1. ¹The Head and Neck Cancer Research Division, Department of Otolaryngology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
2. ²Department of Oncology and Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
3. ³Gustave Roussy Institute, Division of Cancer Medicine, 39 Rue Camille Desmoulins, Villejuif 94805, France
4. ⁴Molecular Biology Laboratory, Department of Thoracic/Head and Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
5. ⁵Pathology Department, Hospital Tenon, AP-HP, 4 rue de la Chine, Paris 75020, France

Correspondence: C Moon, The Head and Neck Cancer Research Division, Department of Otolaryngology, The Johns Hopkins School of Medicine, 818 Ross Research Building, 720 Rutland Ave., Baltimore, MD 21205-2196, USA. E-mail: cmoon5@jhmi.edu

Received 3 February 2003; Revised 29 April 2003; Accepted 6 May 2003.

Abstract

Aquaporins (AQPs) are important in controlling water permeability. As AQP1 is known as a serum-responsive gene, we hypothesized that AQP expression may be involved in the development of human cancer. By reverse transcriptase–polymerase chain reaction analysis, expression of AQPs 1, 3, and 5 was found in seven colon and colorectal cancer cell lines. Western blot analysis confirmed their expression in four of these cell lines. In situ hybridization demonstrated that during colorectal carcinogenesis, the expression of AQPs 1 and 5 was induced in early-stage disease (early dysplasia) and maintained through the late stages of colon cancer development. Expression of AQPs 1 and 5 was maintained even in metastatic lesions in the liver. These findings demonstrate that the expression of several AQPs is found in tumor cells and is associated with an early stage of colorectal cancer development. These novel observations suggest that multiple AQP expression may be advantageous to tumorigenesis, which may lead to a better understanding of colorectal carcinogenesis.