| Objective: Malignant melanoma(MM), is a kind of severe malignant tumors stems from melanocyte, which involves in a variety of tissues and organs, and about90% occurred in skin, 10% in the the iris, ciliary body, choroid, mucous membranes of the digestive,tract mouth and urogenital system, and sometimes in the choroid of the meninges. According to the onset, origin, course and prognosis of of the MM, the MM can be divided into two categories, named in situ MM and invasive MM. In recent years,the incidence of malignant melanoma skin show a clearly rising trend.At present, the primary indicator to predict the liability of MM is still the 1970’s Breslow tumor thickness of the conventional pathology. And the secondary indicator is the general detection of pathological section which is based on the nonspecific pathologic indexes, such as Clark levels, ulcers, mitotic rates, lymphocytes that infiltrating tumor, the invasion of blood and vessels, vascular tendency, pathological staging of lymph nodes, satellite lesions, excessive metastasis and degeneration.Microtubule associated proteins(MAPs) belong to a protein family participating in the formation of microtubule. Locating in the axons and dendrites of neurons, which mainly exist in the central and peripheral nervous system. However, some MAPs, such as the microtubule associated protein 1( MAP1), microtubule associated protein 2(MAP2), microtubule associated protein 4( MAP4), are also generally expressed in the non-neuronal cells [2.3].Recent studies have found that the white people’s MAP2 expressed both in benign pigmented nevus and malignant melanoma tissues, and is associated with the invasive of MM. Meanwhile, many biological characteristics of MM are closely related to the human race. Given the incidence of MM increased year by year in our country, this study intends to discuss the correlation between geneexpression of MAP2 and malignant melanoma invasion.Methods: a retrospective analysis of 43 patients’ paraffin embedding piece which are diagnosed with malignant melanoma by the pathology department of Dalian Medical University’s first affiliated hospital from 2001-2013. For 17 cases are in situ and 26 cases are invasive. All the patients are middle-aged or old patients, including female 23(53.48%), male 20(46.52%), and 7(16.28%) patients occurred in head and face, the remaining 36(83.72%) in the limbs. Of all, only 5(11.63%) patients have lymphatic metastasis, we differentiated them by Clark and Breslow classification. Then we conducted the correlation analysis between the expression of MAP2 and the Clark&Breslow classification, tumor metastasis rate, sex, pathogenic site and clinical types.Processing statistical analysis by SPSS 17.0 software.Results : For all patients’ MAP2 expression, the negative(-) accounts 12 cases,positive(+) 16 cases, strong positive(+ +) 15 cases. According to the analysis results,the expression of MAP2 has no relationship with the patients’ sex, pathogenic site,metastasis rate(P > 0.05), which has no statistical significance, but, with the clinical classification and grade of Clark and Breslow classification it has statistical significance(P < 0.05).Discussion: According to the results of immunohistochemical analysis, MAP2 were induced existing in the primary melanoma of the skin, but not in the metastatic melanoma. Then we assumed that the induction of stable microtubule protein in primary melanoma could destroy the unstable microtubule so as to inhibit the cell division,prevent or delay the tumor’s progression. Further studies confirmed that the MAP2 positive patients have a better metastatic disease-free survival than MAP2 negative patients. For the potential mechanism of MAP2 in melanoma research,MAP2,expressing in metastatic melanoma cells, can lead to the stability of microtubules, stagnate the cell cycle by G2- M phase and then cell growth was inhibited. The destruction of the microtubules’ dynamic caused by MAP2 can stimulate the formation of the mitotic spindle, defects of cytoplasm and accumulation of megakaryocyte. This is similar to the MAP2 positive primary melanoma cells. Thesedata suggest that in the early stages of melanoma, the differentiation of neurons can block cell division, then inhibit or delay tumor metastasis.Conclusion:1. The clinical specimens of MAP2 appears high expression in the early stage of vertical and radial growth of MM, but low or lost expression in the metastatic MM.2. MAP2 is a prognostic indicators of melanoma progression, also is a forecast for the invasion of primary melanoma. |
