| Cell adhesion molecules (CAMs) are a general term of several glycoproteins on cell membrane. CAMs take intercellular adhesion and mediate the cell-cell and cell-extracellular matrix interactions. By their genetic codes and molecular structures, CAMs can be divided into four major subgroups: selectins, integrins, cadherins and an immunoglobulin superfamily.Intercellular adhesion molecule-1 (ICAM-1) belongs to the immunoglobulin superfamily. ICAM-1 has two forms. They are a membrane-bound form (ICAM-1) and a soluble form (sICAM-1). ICAM-1 is an accessory molecule stabilizing the T-cell receptor-mediated binding between antigen-presentingcells and T lymphocytes, and serves as a cofactor in the activation of the cellular immune response. The sICAM-I is smaller than its membranous form, but its ability to bind to lymphocytes-function-associated antigen (LFA-1) is still conserved. Therefore sICAM-1 may competitively bind to LFA-1 expressed on lymphocytes, followed by the result that lymphocytes cannot adhere to the target cells which express membranous ICAM-1. For this reason, sICAM-1 may bring about inhibition of lymphocyte functions.It has been reported by recent investigations that serum levels of sICAM-1 increased in some malignant tumors, involving squamous cell carcinomas of head and neck. The increased levels were even well related to the size of tumor, the situation of metastasis and the prognosis of diseases. Serum levels of sICAM-1 of patients with laryngeal carcinoma could also be higher than that in control group. Moreover the levels increased with the tumor progressing. However, it remains unclear whether ICAM-1 expression hi tissues of laryngeal carcinomas is changed.The purpose of the present study was to examine ICAM-1 expression in tissues of laryngeal carcinomas, through which we could discuss the relationship between the ICAM-1 expression in tissues and the increased levels of serum sICAM-1. We try to provide preliminary evidences to further elucidate the role ICAM-1 plays in tumor immunity, and we also hope our investigation may be useful to develop a biotherapy of laryngeal carcinomas.1. Materials and MethodsAbout 50-100mg tumor tissues were obtained from the 26 patients who were operated for laryngeal carcinoma. Among 25 control specimens, 7 cases weretaken from the laryngeal mucosa, which were at least 2.0 cm, away from the tumor margins and other 18 cases were taken from frontal wall mucosa of 2-4 rings of tracheas. All the cases were pathologically diagnosed. The obtained specimens were immediately executed, and cell suspensions were stored at 4癈. 100ul cell suspensions incubated with 10ul of anti-ICAM-1 monoclonal antibody conjugated with FITC (fluorescein isothiocyanate). Flow cytometer was applied for measuring the percentage of the ICAM-1 expressing-positive cells.2. ResultsThe percentage of ICAM-1 expressing-positive cells was higher in laryngeal carcinoma tissues than that hi the control specimens, as shown in Table 1. The difference between them was statistically significant (f =2.843, P<0.01).Table 1 The percentage of ICAM-1 expressing-positive cells in tissues of laryngeal carcinomas and control specimensGroupCasesICAM-1(+) ( ?SEM) (%)Laryngeal carcinomas2654.81 ?.22Conlrol specimens2535.30?.41No difference could be found between patients with lymph node metastases (47.92?.18%) and those with localized tumor (59.12?.05%) (t=-1.275,According to UICC (1987) stage outline for malignant tumor of head andneck, The percentage of ICAM-1 expressing-positive cells appeared higher in stage I ~ II samples (63.28 ?5.36%) than it was in III-IV stage samples (48.61 ?.78%). Unfortunately, the difference between them was not statistically significant(t=1.861,P=0.075).3. Discussion and ConclusionsThe percentage of ICAM-1 expressing-positive cells was higher in laryngeal carcinoma tissues than it was in the control specimens. This indicated that ICAM-1 expression in laryngeal mucosa may up-regulated after ca...
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