Analysis of TIMP-1 expression in leukoplakia and oral squamous cell carcinoma

ABSTRACT Introduction: The current study about transition of oral epithelial dysplasia, present in lesions such as leukoplakia, for squamous cell carcinoma (SCC) involves not only the histopathological aspects, but also the analysis of the presence of biomarkers which influence the microenvironment where cells are embedded. Objective: To evaluate the tissue inhibitor of metalloproteinase-1 (TIMP-1) profile in cases of leukoplakia and SCC classified into different degrees of dysplasia and histological grading, respectively. The immunohistochemical findings were confronted with microscopic features adopted in the classification of each lesion. Material and methods: Cases of leukoplakia and SCC were recovered from files of The Oral Pathological Anatomy Service of the Dental School at the Universidade Federal do Espírito Santo (SAPB-UFES), between the years 2004 and 2010. New slides were obtained and submitted to immunohistochemical assay to determine TIMP-1 expression profile. Parenchyma, as well as the different layers of the epithelium and stroma was evaluated. Results: In all cases the presence of TIMP-1 was detected in the stroma and parenchyma. In mild leukoplakia, the basal layer with hyperplasia showed intense immunolabeling, whereas cells with loss of polarity presented weaker expression. In moderate leukoplakia, all epithelium layers, except the cornea, were labeled. Severe leukoplakia had the spinous layer most intensely labeled, with no variation in areas with pleomorphism. Stage I SCC showed the deepest islands with intense labeling in cells with pleomorphism and mitoses. In the tumor islands, less differentiated cells were weakly labeled, and in keratin pearl, labeling was weak or absent in central cells. In stage II SCC, labeling was observed in basal cell with hyperplasia and in cells of the spinous layer, however, the parabasal layer was not labeled. Also, on tumor islands, less differentiated cells did not express the protein and keratin pearls were not labeled. Conclusion: It was possible to detect TIMP-1 immunolabeling in all specimens, ranging in intensity and location. The absence of expression in less differentiated cell suggests that more aggressive lesions present reduced enzyme expression. The microenvironment is important for the various cellular activities, and TIMP is an enzyme that participates in matrix remodeling, therefore changes in its expression can be a valuable tool in the better understanding oral carcinogenesis.

摘要
引言：当前关于口腔上皮异常增生（oral epithelial dysplasia，见于白斑等病变）向鳞状细胞癌（squamous cell carcinoma, SCC）转化的研究，不仅涉及组织病理学层面，还包含对影响细胞所处微环境的生物标志物的分析。
目的：分别针对不同异常增生程度的白斑病例，以及不同组织学分级的鳞状细胞癌病例，评估其基质金属蛋白酶组织抑制剂-1（tissue inhibitor of metalloproteinase-1, TIMP-1）的表达谱。将免疫组织化学检测结果与各类病变分类所采用的镜下特征进行对照分析。
材料与方法：研究病例取自2004至2010年间圣埃斯皮里图联邦大学牙科学院口腔病理解剖服务中心（Universidade Federal do Espírito Santo, SAPB-UFES）的档案库，涵盖白斑与鳞状细胞癌病例。制备新的组织切片并开展免疫组织化学检测，以确定TIMP-1的表达谱。分别对实质组织、上皮的各层结构以及间质进行评估。
结果：所有病例的间质与实质组织中均检测到TIMP-1的表达。轻度白斑中，伴增生的基底层呈现强免疫标记，而极性丧失的细胞则表现为较弱的表达。中度白斑中，除角质层外的所有上皮层均被标记。重度白斑的棘层标记最为强烈，在多形性区域未见表达差异。I期鳞状细胞癌的最深肿瘤岛中，伴多形性与核分裂象的细胞呈现强标记；肿瘤岛中分化程度较低的细胞标记较弱，角化珠中央的细胞则标记微弱或无标记。II期鳞状细胞癌中，伴增生的基底层与棘层细胞可见标记，但副基底层无标记；肿瘤岛中分化较低的细胞不表达该蛋白，角化珠亦无标记。
结论：所有标本中均检测到TIMP-1的免疫标记，其表达强度与定位存在差异。低分化细胞中无该蛋白表达，提示侵袭性更强的病变中该酶的表达水平降低。微环境对多种细胞活动至关重要，而TIMP作为参与基质重塑的酶，其表达变化可为深入理解口腔癌变机制提供有价值的研究工具。