[Changes of the elastic fibers and collagen fibers during the development and progression of experimentally induced tongue carcinoma in hamsters].

OBJECTIVE: To investigate the relationship between the extracellular matrix (ECM) and neoplastic progression in hamster with tongue cancer. METHODS: Forty-eight specimens of hamster tongue cancer were divided into control group (n=6) and experimental group (n=42). The pathological grade of the specimens was assessed (including 3 stages, namely atypical hyperplasia, carcinoma in situ and early invasive carcinoma). The sections of the tongue were stained with Masson and aldehyde-fuchsin (AF) staining for microscopic observation of the elastic fiber and collagen fiber changes. RESULTS: Within the connective tissue cores (CTC) of the papillae in the control group was a framework of numerous and fine Gomrori's aldehyde fuchsin-positive elastic fibers. But in the stages of dysplasia and carcinoma in situ, these elastic fibers decreased and further diminished in the CTC in early invasive carcinoma. In dysplasia and carcinoma in situ stages, most of the elastic fibers collapsed with scattered elastic fibers, and the elastic fibers decreased significantly in early invasive carcinoma. The control group showed a significantly greater number of elastic fibers in the experimental group. The collagen fiber was obviously increased and irregularly arranged in dysplasia and carcinoma in situ stage; in early invasive carcinoma, the collagen fibers became thicker with deposition in the lamina propria. CONCLUSION: An excessive deposition of collagen fiber and reduction of the elastic fibers is an important factor contributing to the development of tongue carcinoma in hamsters.

GA binding protein regulates interleukin 7 receptor alpha-chain gene expression in T cells.

The interleukin 7 receptor alpha-chain (IL-7Ralpha) is essential for T cell development in both humans and mice and for B cell development in mice. Whereas the transcription factor PU.1 regulates IL-7Ralpha expression in mouse pro-B cells via a GGAA motif, we demonstrate here that GA binding protein (GABP) bound to this site and was essential in the regulation of IL-7Ralpha expression in T cells, where PU.1 is not expressed. Moreover, IL-7Ralpha expression was diminished substantially in thymocytes but was normal on B220(+) fetal liver cells from mouse embryos with diminished expression of GABPalpha. Thus, GABP is essential for the regulation of IL-7Ralpha expression in T cells, and the differential regulation of IL-7Ralpha in distinct lymphoid lineages is achieved at least in part by differential recruitment of factors to the same GGAA motif.