Study On Clinical Pathology And Disfunction Of P16-Cyclin D₁-pRb Pathway Of Primary Oral Mucosal Malignant

Primary oral mucosal malignant melanoma(POMMM) is a rare malignant tumor. Its histomorphology is complicated.The disease has a high metastasis and recurrence rate,and the prognosis is poor.The researchs on it in the world have less cases, and most of them are lack of follow-up information. Many studies suggest that the occurrence of malignant tumor has relation to cell cycle control. The disfunction of p16-Cyclin Di-pRb pathway is found in sporadic skin malignant melanoma, genetic malignant melanoma and choroidal melanoma and has relation to the occurrence and development of tumor. The same research in POMMM hasn't been reported in the world .Objectives: The aims of this study were:1. to investigate the association between clinical and pathological characteristics of POMMM and the prognosis of this disease.2.to explore the possible mechanism of occurrence and development of POMMM .Methods:1. Clinical and pathological characters of 73 cases POMMM wereinvestigated. The association between risk factors, such as black macule, lymph node metastasis, invasive depth, clinic stage, pathologic type, and prognosis was analyzed using Kaplan-Meier survival analysis and Log rank test.2.1mmunohistochemical method was applied to detect the expression of p16, Cyclin DI , pRb in 30 cases of POMMM.Results:1. The age of the patients ranged from 24 to 80(Median age,50). Amongthe patients ,43 cases were males and 30 were females.The most common locations of the tumor were palate and gingiva.2. The clinical stages of these patients were shown as the following: Stage 1(46/73), Stage 11(24/73), StageIII(3/73). The most common pathological type was nodular(44/73), followed by lentiginaus malignant melanoma (15/73) and superficial spreading(l/73). According to the configuration of tumor cells , the most common type was the mixed cell type (37/73), followed by the epithelial type (27/73) and the spindle cell type(9/73).3. Among the 73 patients, 43 were followed up, the 3-year and 5-year survival rate is 19.9% and 11.9% repectively. The median survival time is 18.0 month.4. Black macule, lymph node metastasis, invasive depth, clinicstage, pathologic type, treatment method are related to prognosis(P<0.05). Black macule is related to pathologic type(P<0.05). Most cases with black macule are belong to lentiginaus type.5. InPOMMM, the abnormal rate of p1 6, Cyclin D1, pRbis53.3%, 36.7%, 13.3% whereas in BN is 0.0%, 5.0%, 0.0%. There is obvious statistics difference between benigh and malignant group(P<0.05).6.86.7% of cases have at least one abnomal protein expression. There is an inverse relatuinship between P16 and pRb(P<0.05). P16 is related to Cyclin D|. More cases overexpress Cyclin D1 in P16-positive group.Conclusions:1 . The prognosis of POMMM is associated with black macule, lymph node metastasis, invasive depth, clinic stage, pathologic type, treatment methods.2. Abnormality of PI 6- Cyclin Di-pRb way often occurrs in POMMM, and it has some diagnostic value in benign-malignant diagnosis. The three elements has mutual relationship . They maybe mutual regulation during their biological progression.