Immunohistochemical characterization of FHIT expression in normal human tissues

Abstract

Abstract:Background: Fragile histidine triad (FHIT) is a tumor suppressor gene that is commonly inactivated in human tumors. Interestingly, the normal pattern of FHIT expression is largely unknown. Aim: This study is aimed to characterize the expression of FHIT protein in normal human tissues. Materials and methods: A total of 119 normal human tissue specimens were analyzed for the FHIT expression using immunohistochemistry technique. The inclusion criteria included: normal/infl ammatory tissue with no evidence of cellular atypia. Results: All studied specimens were stained positively with FHIT and showed either nuclear or cytoplasmic expression. Interestingly, the pattern of FHIT staining was similar among diff erent specimens from each organ. FHIT is located predominantly in the nucleus, although cytoplasmic staining is also present in some cell types. Oral squamous epithelium, breast ductal epithelium, squamous and tubal metaplastic epithelium of the uterine cervix, esophageal squamous epithelium, salivary glands, and bronchial epithelia all strongly expressed the nuclear protein. In connective tissue, FHIT has shown strong cytoplasmic expression in histocytes including macrophages and dendritic cells, fi broblasts, and myofi broblasts. Conclusion: Documentation of the pattern of FHIT expression in normal tissues will contribute to our understanding of the normal function of this protein and to interpretation of potentially altered FHIT expression in human tumors.

FHIT, a Novel Modifier Gene in Pulmonary Arterial Hypertension

“…The tumor suppressor gene FHIT is readily lost after exposure to carcinogens or stressors, such as cigarette smoke and ultraviolet irradiation (14,15). FHIT is highly expressed in the lung (16) but is commonly lost in lung cancer and other malignancies (17,18). Moreover, FHIT is implicated in apoptosis and proliferation in various cell types (19,20), potentially linking it to the abnormal proliferative phenotype observed in PAH endothelial and smooth muscle cells (PASMCs).…”