背景:癌症干细胞(CSC)从头或通过将口腔潜在恶性疾病(OPMD)转化为口腔鳞状细胞癌(OSCC)来启动癌变过程。这项研究的目的是检测胚胎型CSC标志物OCT3/4和SOX2在OSCC和口腔白斑(OLs)中的表达,最常见的OPMD。
方法:研究类型为实验性,研究设计的特点是半定量研究,属于实验研究的分支。该实验是在口腔医学/病理学系进行的,牙科学院,塞萨洛尼基亚里士多德大学,希腊。本研究重点研究了21例不同分化程度的OSCC和30例不同发育异常程度的OLs石蜡包埋样本中CSCs蛋白生物标志物SOX2和OCT3/4表达的半定量免疫组织化学(IHC)模式。与5例正常口腔粘膜的细胞染色阳性和强度相比。通过SPSS2017Pearson卡方进行统计分析,显著性水平设定为0.05(p=0.05)。通过定量聚合酶链反应(qPCR)研究SOX2和OCT3/4各自基因的表达,使用独立配对T检验,在12例轻度/非发育不良的OLs和19例中度/低分化的OSCCs(n=19)和5例正常粘膜的石蜡包埋样本中。
结果:SOX2和Oct3/4基因在所有受检病例中均有表达,尽管在正常人之间无统计学意义的相关性,OL和OSCC,已建立。仅在21个OSCC中的3个中观察到OCT3/4的核/膜染色,但在OLs或正常病例中均无(无统计学意义)。在大多数样品中注意到SOX2的特征性核染色,主要在上皮的基底层和副基底层。SOX2在OSCCs组中检测到(17/21强阳性)显著高于OL组(30例,大多轻度染色)(p值=0.007),和正常的口腔上皮(轻度染色,p=0.065)。此外,SOX2在分化良好的OSCC组中过表达(5/OSCC,强烈染色),而不是轻度发育不良和非发育不良的OLs样品(14/OLs,轻度染色)(p值=0.035)。
结论:SOX2的特征性表达而非OCT3/4在OLs'和OSCCs'病变中的特征性表达表明存在具有某些CSC特征的肿瘤细胞,其在口腔肿瘤发生的早期阶段的意义可以进一步评估。SOX2作为预后因素的临床应用,需要在更多的样品中进行进一步的实验评估。
BACKGROUND: Cancer stem cells (CSCs) are incriminated for initiating the process of carcinogenesis either de novo or through the transformation of oral potentially malignant disorders (OPMDs) to oral squamous cell carcinoma (OSCC). The aim of this
study was to detect the expression of embryonic-type CSC markers OCT3/4 and SOX2 in OSCCs and oral leukoplakias (OLs), the most common of OPMDs.
METHODS: The
study type is experimental, and the
study design is characterized as semiquantitative research, which belongs to the branch of experimental research. The experiment was conducted in the Department of Oral Medicine/Pathology, School of Dentistry, Aristotle University of Thessaloniki, Greece. This
study focuses on the semiquantitative immunohistochemical (IHC) pattern of expression of CSCs protein-biomarkers SOX2 and OCT3/4, in paraffin embedded samples of 21 OSCCs of different grades of differentiation and 30 cases of OLs with different grades of dysplasia, compared to five cases of normal oral mucosa in both terms of cells\' stain positivity and intensity. Statistical analysis was performed through SPSS 2017 Pearson Chi-square and the significance level was set at 0.05 (p=0.05). The expression of the respective genes of SOX2 and OCT3/4 was studied through quantitative polymerase chain reaction (qPCR), in paraffin-embedded samples of 12 cases of OLs with mild/non dysplasia and 19 cases moderately/poorly differentiated OSCCs(n=19) and five normal mucosa using the Independent Paired T-test.
RESULTS: The genes SOX2 and Oct3/4 were expressed in all examined cases although no statistically significant correlations among normal, OL and OSCC, were established. A nuclear/membrane staining of OCT3/4 was noticed only in three out of 21 OSCCs but in none of OLs or normal cases (without statistical significance). A characteristic nuclear staining of SOX2 was noticed in the majority of the samples, mostly in the basal and parabasal layers of the epithelium. SOX2 was significantly detected in the OSCCs group (strong positivity in 17/21) than in the OL group (30 cases, mostly mildly stained) (p-value=0.007), and the normal oral epithelium (mild stained, p=0.065). Furthermore, SOX2 was overexpressed in well differentiated OSCCs group (5/OSCCs, strongly stained) rather than in mildly dysplastic and non-dysplastic OLs samples (14/OLs, mildly stained) (p-value =0.035).
CONCLUSIONS: The characteristic expression of SOX2 but not of OCT3/4 in OLs\' and OSCCs\' lesions suggests the presence of neoplastic cells with certain CSC characteristics whose implication in the early stages of oral tumorigenesis could be further evaluated. The clinical use of SOX2, as prognostic factor, requires further experimental evaluation in larger number of samples.