Immunohistochemical analysis of Ki-67 and α-SMA in odontogenic keratocyst, ameloblastoma and pericoronal follicle

Abstract Introduction Ameloblastomas (AM) are considered the most common odontogenic tumors, with great clinical importance linked to its locally aggressive, infiltrative, and recurrent behavior. The odontogenic keratocyst (OK) represents a peculiar cyst that also draws attention because of its aggressive behavior and high rates of local recurrence. Objective The aim of this study was to evaluate the cell proliferation index and the presence of myofibroblasts in AM and OK using Ki-67 and α-SMA antibodies, respectively. Methodology Fifteen cases of AM and 24 cases of OK were selected for immunohistochemical investigation of the proteins α-SMA and Ki-67. A group of 7 pericoronal follicles (PF) was included as control for normal odontogenic tissue. The mean percentage of positive cells was calculated for each protein. Result Kruskal-Wallis test for both markers showed that expression was higher in OK, when compared to AM and PF. Mann-Whitney test showed no statistical difference when comparing the expression of both markers between the subtypes of AM. Conclusion Elevated expression of Ki-67 and α-SMA in OK may be associated with the aggressive clinical behavior of this cyst in comparison to other development cysts. The similar expression of the markers observed among AM and PF cases, as well as among subtypes of AM, may indicate that other factors, besides proliferative potential, are associated with the aggressive behavior of AM.

引言：成釉细胞瘤（Ameloblastomas, AM）是临床最常见的牙源性肿瘤，因其具备局部侵袭性、浸润性及复发性的生物学特性，临床意义重大。牙源性角化囊肿（odontogenic keratocyst, OK）作为一类特殊的囊性病变，同样因侵袭性生长特点与较高的局部复发率受到广泛关注。
研究目的：本研究旨在分别以Ki-67与α-平滑肌肌动蛋白（α-SMA）抗体为标记物，评估成釉细胞瘤与牙源性角化囊肿中的细胞增殖指数及肌成纤维细胞的表达情况。
研究方法：本研究选取15例成釉细胞瘤病例与24例牙源性角化囊肿病例，针对α-SMA与Ki-67蛋白开展免疫组化检测；另纳入7例冠周滤泡（pericoronal follicle, PF）作为正常牙源性组织对照，计算两种蛋白的阳性细胞平均百分比。
研究结果：针对两种标志物的克鲁斯卡尔-沃利斯（Kruskal-Wallis）检验结果显示，牙源性角化囊肿的标志物表达水平均高于成釉细胞瘤与冠周滤泡；曼-惠特尼（Mann-Whitney）检验结果显示，成釉细胞瘤各亚型间的两种标志物表达水平无统计学差异。
研究结论：相较于其他发育性囊肿，牙源性角化囊肿中Ki-67与α-SMA的高表达或与其侵袭性临床生物学行为相关；而成釉细胞瘤与冠周滤泡间、以及成釉细胞瘤各亚型间的标志物表达水平相似，这提示除细胞增殖潜能外，其他因素或与成釉细胞瘤的侵袭性行为存在关联。