口腔癌前病变、口腔鳞癌中诱导型一氧化氮合酶与p53蛋白表达及细胞增殖相互关系的研究

目的:探讨诱导型一氧化氮合酶(inducible netric oxide synthase,iNOS)在口腔鳞癌发展过程中的表达及与p53蛋白表达和细胞增殖的相互关系。方法:采用免疫组化SABC法检测10例正常口腔黏膜、8例上皮单纯增生、20例上皮异常增生和32例口腔鳞癌组织中iNOS、p53及Ki-67蛋白的表达。结果:口腔鳞癌发展过程中存在着iNOS、p53、Ki-67表达的上调;三种蛋白的表达与上皮异常增生的病理分级有关(P<0.05),与鳞癌的病理分级无关;各组中iNOS和p53表达之间均存在显著正相关(P<0.05);iNOS阳性表达的鳞癌组织中Ki-67标记指数较阴性者显著增高(P<0.05)。结论:iNOS与p53蛋白互为反馈影响,在口腔鳞癌发展过程中意义重大;鳞癌中iNOS的阳性表达可能提示该组织的快速增殖优势。     

口腔癌前病变、口腔鳞癌中诱导型一氧化氮合酶与p53蛋白表达及细胞增殖情况的相互关系的研究

目的探讨诱导型一氧化氮合酶(inducible netric oxide synthase,iNOS)在口腔鳞癌发展过程中的表达及与p53蛋白表达和细胞增殖的相互关系. 方法采用免疫组化SABC法检测10例正常口腔黏膜、8例上皮单纯增生、20例上皮异常增生和32例口腔鳞癌组织中iNOS、p53及Ki-67蛋白的表达. 结果口腔鳞癌发展过程中存在着iNOS、p53、Ki-67表达的上调;三种蛋白的表达与上皮异常增生的病理分级有关(P<0.05),与鳞癌的病理分级无关;各组中iNOS和p53表达之间均存在显著正相关(P<0.05);iNOS阳性表达的鳞癌组织中Ki-67标记指数较阴性者显著增高(P<0.05).结论iNOS与p53蛋白互为反馈影响,在口腔鳞癌发展过程中意义重大;鳞癌中iNOS的阳性表达可能提示该组织的快速增殖优势.     

口腔黏膜良性淋巴组织增生病的免疫组化研究

目的　研究口腔黏膜良性淋巴组织增生病与口腔癌的细胞增殖能力、血管密度和细胞凋亡的变化。方法　采用免疫组化SP法检测 15例黏膜良性淋巴组织增生病、9例黏膜良性淋巴组织增生病伴上皮异常增生、15例口腔癌及 10例正常黏膜组织中Ki 6 7的表达、细胞凋亡及微血管密度。结果　口腔黏膜良性淋巴组织增生病伴异常增生及鳞状细胞癌中Ki 6 7的表达明显高于不伴异常增生的口腔黏膜良性淋巴组织增生病及正常黏膜 (P <0 0 5 ) ,在所有的口腔黏膜良性淋巴组织增生病及鳞状细胞癌中微血管密度均明显高于正常组 (P <0 0 5 )。口腔黏膜良性淋巴组织增生病中细胞凋亡明显高于正常黏膜及口腔癌 (P <0 0 5 )。结论　在伴有上皮异常增生的口腔黏膜良性淋巴组织增生病中Ki 6 7表达及微血管密度均介于正常组织和口腔癌之间 ,凋亡细胞数也明显多于正常组织。研究结果提示 :口腔黏膜良性淋巴组织增生病是一种具有癌变潜能的疾患     

诱导型一氧化氮合酶表达在口腔癌前病变口腔鳞癌发展过程中的作用研究

目的　探讨诱导型一氧化氮合酶 (iNOS)在口腔癌前病变、口腔鳞癌发展过程中的表达情况及其作用。方法　采用免疫组化SABC法检测 10例正常口腔黏膜、8例上皮单纯增生、2 0例上皮异常增生和 3 2例鳞状细胞癌组织中iNOS的表达。结果　正常口腔黏膜iNOS阴性表达 ;上皮异常增生组和鳞癌组中iNOS的表达较上皮单纯增生组均显著增加 (P <0 .0 5 ) ;随着上皮异常增生程度的加重 ,iNOS的标记指数逐级显著上升 (P <0 .0 5 ) ;上皮异常增生组与鳞癌组之间以及鳞癌的各病理分级之间iNOS的表达均无显著性差异 (P >0 .0 5 )。结论　iNOS的表达可能参与了口腔鳞癌的衍进过程     

Expression of p53 in oral mucosal hyperplasia, dysplasia and squamous cell carcinoma

OBJECTIVE: To assess p53 expression in a range of oral mucosal lesions and to relate the results to the clinical outcome in patients with dysplastic oral mucosal lesions and oral squamous cell carcinomas (OSCC).
MATERIALS AND METHODS: Archival tissue was available for eight cases of normal oral mucosa, 50 cases of oral mucosal hyperplasia, 41 cases of oral mucosal dysplasia and 48 cases of OSCC. The monoclonal antibody DO-7, reactive to p53 protein, was applied to paraffin-embedded sections using microwave pretreatment and immu-nohistochemical techniques.
RESULTS: The results showed that normal oral mucosa did not express p53.Positive nuclear staining was found in 18/50 (36%) cases of hyperplasia, 35/41 (85%) cases of dysplasia and 45/48 (94%) cases of OSCC.None of the p53 negative dysplasias progressed, while 19% of p53 positive cases of dysplasia recurred following excision and 11% of the cases underwent neoplastic transformation. Five out of 10 (50%) cases of severe dysplasia which were p53 positive resolved.
CONCLUSION: The proportion of cases with positive p53 expression increased from hyperplasia to dysplasia to OSCC. These results may indicate an involvement of p53 in neoplastic transformation as well as in proliferative events although the presence or absence of p53 staining could not be used to predict the outcome of potentially malignant oral mucosal lesions.     

Elevated ras p21 expression in oral premalignant lesions and squamous cell carcinomas in Taiwan

Expression of ras p21 oncoproteins was examined in histological sections of oral squamous cell carcinoma (SCC), epithelial dysplasia, epithelial hyperkeratosis and normal oral mucosa using antibodies to ras p21 with an immunoperoxidase technique. Ras p21-positive staining was found in 47 of 51 (92.2%) cases of oral SCC, 4 of 4 (100%) cases of epithelial dysplasia, 7 of 7 (100%) cases of epithelial hyperkeratosis, and 1 of 6 (16.7%) cases of normal oral mucosa. The positive staining rate of ras p21 in oral SCC, epithelial dysplasia or epithelial hyperkeratosis was significantly higher than that in normal oral mucosa (P<0.05). No correlation was found between ras p21 expression and patient age, tumour location, tumour size, clinical staging or histological differentiation of SCC. However, a significant positive correlation was found between ras p21 expression and patients' sex (P<0.05) or regional lymph node status (P<0.05). A significant positive correlation was also discovered between ras p21 expression and patients' smoking habits (P<0.01), as well as daily or total betel quid (BQ) consumption (P<0.05). Of the 47 immunostain-positive SCC patients, specimens from 6 patients were also obtained after chemotherapy, when ras p21 expression was found to be reduced. These results indicate that ras p21 over expression may play an important role in the initiation and progression of oral SCCs in patients who are smokers and BQ chewers.     

Immunohistochemical expression of p53, p16 and hTERT in oral squamous cell carcinoma and potentially malignant disorders

Oral carcinogenesis is a multi-step process. One possible step is the development of potentially malignant disorders known as leukoplakia and erytroplakia. The objective of this study was to use immunohistochemistry to analyze the patterns of expression of the cell-cycle regulatory proteins p53 and p16(INK4a) in potentially malignant disorders (PMD) of the oral mucosa (with varying degrees of dysplasia) and in oral squamous cell carcinomas (OSCC) to correlate them with the expression of telomerase (hTERT). Fifteen PMD and 30 OSCC tissue samples were analyzed. Additionally, 5 cases of oral epithelial hyperplasia (OEH) were added to analyze clinically altered mucosa presenting as histological hyperplasia without dysplasia. p53 positivity was observed in 93.3% of PMD, in 63.3% of OSCC and in 80% of OEH. Although there was no correlation between p53 expression and the grade of dysplasia, all cases with severe dysplasia presented p53 suprabasal immunoexpression. p16(INK4a) expression was observed in 26.7% of PMD, in 43.3% of OSCC and in 2 cases of OEH. The p16(INK4a) expression in OEH, PMD and OSCC was unable to differentiate non-dysplastic from dysplastic oral epithelium. hTERT positivity was observed in all samples of OEH and PMD and in 90% of OSCC. The high hTERT immunoexpression in all three lesions indicates that telomerase is present in clinically altered oral mucosa but does not differentiate hyperplastic from dysplastic oral epithelium. In PMD of the oral mucosa, the p53 immunoexpression changes according to the degree of dysplasia by mechanisms independent of p16(INK4a) and hTERT.     

艾滋病感染者口腔疣状肿块人类乳头状瘤病毒感染与P53,Ki-67蛋白过度表达

目的 :了解艾滋病感染者口腔黏膜疣状肿块细胞生物学特性。方法 :应用免疫组织化学法、PCR对艾滋病感染者口腔黏膜疣状肿块、非艾滋病感染者口腔黏膜癌前病变和鳞癌组织中P5 3和Ki 67蛋白、人类乳头状瘤病毒 (HPV ) ,巨细胞病毒 (CMV)和EB病毒 (EBV )进行检测。结果 :( 1)艾滋病感染者口腔黏膜疣状肿块中P5 3蛋白阳性表达率为 2 3 % ,Ki 67蛋白阳性表达率为 76% ,二者均低于非艾滋病感染者口腔黏膜鳞癌(P <0 .0 5 ) ,但与非艾滋病感染者口腔黏膜癌前病变无明显差别 (P >0 .0 5 ) ;( 2 )艾滋病感染者口腔黏膜疣状肿块中 ,HPV感染率为 88.2 % ,明显高与非艾滋病感染者口腔黏膜癌前病变和口腔黏膜鳞癌 (P <0 .0 1)。没有检测到EBV、CMV病毒感染。结论 :艾滋病感染者口腔疣状肿块和HPV感染有关 ,存在抑癌基因突变和细胞过度增殖现象。     

p16,p53,Ki67在口腔癌前病变表达及4年临床随访

目的 :研究 p16,p5 3 ,Ki-67蛋白表达与口腔癌前病变的关系。 方法 :采用免疫组织化学LsAB法对43例上皮异常增生 ( 2 0例轻度上皮异常增生 ,2 3例重度上皮异常增生 )和 2 0例正常口腔黏膜 p16,P5 3和Ki -67蛋白的表达进行研究 ,并对上皮异常增生患者实际癌变率做了 4年追踪。结果 :正常黏膜组 ,p5 3不表达 ,Ki -67少量表达 ,p16的阳性表达为 10 0 %。轻度上皮异常增生 ,p5 3 ,Ki-67少数表达 ,p16表达率为 86.96%。重度上皮异常增生 ,p5 3和Ki-67过度表达 ,p16表达明显下降 ,与正常黏膜 ,轻度上皮异常增生相比差异显著 (P <0 .0 5 )。p5 3和Ki-67蛋白过度表达而 p16呈低表达与实际口腔癌前病变癌变率有一定相关性。 结论 :口腔黏膜癌变是一个由量变到质变的过程 ,它们的调控基因 p16,p5 3 ,Ki -6发生了显著的变化 ,可能起着重要的调控作用。     

Increase of mast cells and tumor angiogenesis in oral squamous cell carcinoma

BACKGROUND: Although mast cells (MCs) have been implicated in promoting angiogenesis in some malignant tumors, especially of the aerodigestive tract, little is known in oral squamous cell carcinoma (SCC). METHODS: A retrospective study was conducted to elaborate upon the correlation between MCs and tumor angiogenesis in 26 cases of oral SCC, six cases of oral pre-malignant dysplasia, 10 cases of oral hyperkeratosis, and six cases of normal oral mucosa by means of immunohistochemical technique. RESULTS: The MCs in all lesions and normal oral mucosa strongly expressed tryptase. The densities of MCs and microvessels appeared to increase with disease progression. The MC and microvascular counts were significantly higher in oral SCC than in hyperkeratosis and normal oral mucosa (P < 0.05). A significant correlation between MC and microvascular densities was observed in oral SCC (r = 0.5; P = 0.012). CONCLUSIONS: These findings suggest that MCs may upregulate tumor angiogenesis in oral SCC, perhaps via MC tryptase.     

口腔鳞癌发展过程中抑癌基因PTEN的蛋白表达及意义

目的：探讨抑癌基因PTEN(phosphatase and tensin homologue deleted on chromosome ten)在口腔鳞癌(oral squamous cell cancer，OSCC)发展过程中的蛋白表达及临床病理意义。方法：应用免役组化S—P法检测10例正常口腔粘膜、10例上皮单纯增生、15例上皮异常增生及32例OSCC组织中抑癌基因PTEN的蛋白表达情况，同时结合患者的临床病理资料进行分析。结果：正常口腔粘膜和上皮单纯增生组织中VTEN蛋白全部阳性表达；上皮异常增生组织中PTEN蛋白阳性表达率为93．3％；OSCC组织中PTEN蛋白的阳性表达率为71．9％，其中高、中、低分化OSCC组织中PTEN蛋白的阳性表达率分别为85．7％、75％和33．3％。PTEN在OSCC组织中的蛋白表达与患者的性别、年龄无明显相关性，但与组织分化程度明显相关。结论：OSCC组织(尤其低分化)中PTEN蛋白的阴性表达率较高．说明PTEN基因突变或缺失在OSCC的发生、发展过程中起重要作用。     

RB1CC1在人和小鼠口腔癌发生发展中表达的比较研究

目的:比较视网膜母细胞瘤RB1-诱导卷曲蛋白1(RB1CC1)在人和小鼠正常口腔黏膜、上皮异常增生组织及口腔鳞状细胞癌中的表达,并探讨其在口腔癌发生发展过程中的作用。方法:采用免疫组化和RT-PCR检测人及小鼠在正常口腔黏膜、上皮异常增生、高分化鳞癌原发灶组织中RB1CC1蛋白及基因的表达情况。结果:RB1CC1蛋白在人上皮异常增生组、高分化鳞癌组的阳性表达高于正常组(P<0.05);RB1CC1蛋白在鼠正常组、异常增生组、高分化鳞癌组阳性表达逐渐增加,差异均有统计学意义(P<0.05)。人RB1CC1 mRNA的表达量在异常增生组与高分化鳞癌组无明显差异,正常口腔黏膜组均高于异常增生组与高分化鳞癌组(P＜0.05);小鼠RB1CC1 mRNA的表达量在正常口腔黏膜组与异常增生组、高分化鳞癌组差别无统计学意义。结论:RB1CC1表达在人和小鼠相似, RB1CC1可能参与了口腔鳞癌的早期癌变过程。     

Expression of p16 in oral cancer and premalignant lesions

Background:  Expression of p16 has been proposed as a marker for malignant transformation. This study aimed to evaluate p16 expression in oral squamous cell carcinoma (OSCC) and premalignant lesions including oral leukoplakia (OL) with and without dysplasia.
Methods:  Expression of p16 was investigated in 56 samples including OSCC, OL with and without dysplasia, and normal oral mucosa. Expression of p16 was identified by immunohistochemistry, using the CINtecTM p16INK4a Histology Kit. Both nuclear and/or cytoplasmic staining of the keratinocytes were considered to be positive and the percentage of positive cells was calculated.
Results:  Expression of p16 was detected in 3/16 (18.75%) cases of OSCC, in 4/15 (26.7%) cases of OL without dysplasia, and in none of OL with dysplasia and normal mucosa. No significant differences in p16 expression prevalence were found among OSCC, OL with and without dysplasia and normal mucosa. The percentages of positive cells in OSCC and OL without dysplasia were 0.89 and 0.17, respectively. No significant difference in the percentage of positive keratinocytes was found.
Conclusion:  As a marker, p16 is not reliable for oral mucosal dysplasia and malignant transformation.     

Assessment of p63 expression in oral squamous cell carcinomas and dysplasias

OBJECTIVES: p63, a p53 homologue, may be associated with tumorigenesis in epithelial tissues through its inhibition of p53 transactivation functions. We sought to determine the pattern and levels of p63 expression in oral dysplasias and carcinomas using standard immunohistochemical staining. We also assessed and compared expression of p53 and a cell proliferation marker in these lesions. STUDY DESIGN: This retrospective cross-sectional survey (n=67) included hyperkeratosis (10), mild dysplasia (9), moderate dysplasia (11), severe dysplasia/in situ carcinoma (10), squamous cell carcinoma (SCC) (22 [9 well differentiated, 7 moderately differentiated, 6 poor differentiated]), and normal mucosa (5). Serial sections were stained immunohistochemically with antibodies to p63 (4A4 recognizing all p63 isotypes), p53 (DO-7), and Ki-67 (MIB-1) proteins. In preinvasive lesions, both the percentage of positive cells and staining patterns (negative, basal, suprabasal) were assessed. In oral SCCs, the percentage of positive cells was assessed. Statistical analysis was done using the Tukey-Kramer multiple comparisons test. RESULTS: A suprabasal p63 staining pattern was evident in keratinocyte nuclei in the entire range of noninvasive lesions studied, including normal mucosa. Most nuclei in invasive SCCs stained positive. When all grades of dysplasia were combined, the percent of p63 positive cells was significantly greater than hyperkeratosis (P < .01), and well-differentiated SCC (P < .001). Moderately differentiated SCC had statistically significant more positive cells than well-differentiated SSC (P < .01). Comparison of serial sections showed different p63 staining patterns compared to p53 or Ki-67 staining patterns. CONCLUSIONS: We conclude that p63 is expressed in oral carcinomas and dysplasias, as determined by immunohistochemical staining with a primary antibody to all isotypes. Neither staining pattern nor percentage of stained cells could be used to differentiate the lesions studied. The statistically significant differences found between some groups are not likely to be of diagnostic value. p63 is not coexpressed with p53 expression or Ki-67 suggesting functional independence. When antibodies to the p63 isotypes become available, oral dysplasias and carcinomas should be reassessed.     

Role of TP53 in the progression of pre-malignant and malignant oral mucosal lesions. A follow-up study of 144 patients

Background:  Prediction of progression from pre-malignant oral mucosal lesions to malignancy, or recurrence of an existing oral squamous cell carcinoma (OSCC), is an important clinical problem in oral medicine.
Methods:  This study presents a follow-up of a study published in 2002. Samples from 54 patients with OSCC, 45 with oral lichen planus (OLP) and 45 with hyperkeratosis (clinically leukoplakia), diagnosed between 1987 and 1996, were analysed for TP53 protein expression and TP53 mutation. Follow-up was 11–17 years for OSCC (mean 13.3), 12–22 years for OLP (mean 15.9) and 12–17 years for hyperkeratosis (mean 14.5).
Results:  Of the 54 OSCC patients, 28 experienced recurrent disease, 21 died of OSCC, 22 died of other causes. Of the 14 OSCC patients with mutated TP53 ( n  = 11), the cancer recurred in eight (57%) and in 20/39 (51%) without mutation. Expression of TP53 protein was significantly associated with reduced overall survival. Among OLP patients, nine were TP53- mutated out of 31 tested. One TP53- mutated OLP patient developed OSCC in a different site. Of the hyperkeratosis patients, three were mutated of 22 tested. One hyperkeratosis patient (non-mutated) developed OSCC in the same site.
Conclusion:  TP53 mutations can exist in benign oral mucosal lesions for many years without progression to malignancy. No association was found between TP53 protein expression or TP53 mutation and recurrence of OSCC or disease-related survival. Overall survival was reduced in patients with positive TP53 protein expression.     

口腔黏膜癌变过程中Slit蛋白的表达及其与血管生成的关系

目的:研究Slit蛋白在口腔黏膜癌变过程中的表达及其与肿瘤血管形成的关系。方法:采用免疫组织化学Envision法检测40例人口腔鳞状细胞癌、18例上皮单纯增生、20例上皮异常增生、20例原位癌及19例正常口腔黏膜标本Slit、VEGF的表达和MVD。结果:口腔鳞癌组中有34例Slit表达阳性,与正常黏膜组及癌前病变组相比有显著性差异(P<0.01),而19例正常口腔黏膜仅有1例表达为弱阳性,与原位癌组及上皮异常增生组之间有显著性差异(P<0.01,P<0.05)。VEGF的表达趋势与Slit蛋白一致,Slit蛋白和VEGF表达均与MVD呈显著正相关(P<0.01)结论:口腔鳞癌癌变过程中Slit蛋白阳性表达与其恶性程度呈正相关,Slit在口腔鳞癌中有促血管形成的作用,并可能对口腔鳞癌的发展过程起重要作用。     

Expression of apoptotic and cell proliferation regulatory proteins in actinic cheilitis

BACKGROUND: Actinic cheilitis (AC) is a pre-malignant lesion caused by ultraviolet (UV) radiation. The apoptotic proteins p53, bax, bcl-2, and the proliferation marker Ki-67, are known to play an important role in UV-exposed skin and carcinomas, therefore, these markers were assessed in AC and compared with normal lip and oral mucosa. METHODS: AC (n = 13), normal lip (n = 7) and oral mucosa (n = 6) biopsies were stained immunohistochemically for p53, bax, bcl-2 and Ki-67, to determine their expression and distribution. RESULTS: p53 was over-expressed in AC as compared with normal lip and oral mucosa (P < 0.003). Although bcl-2 expression was higher in AC than in oral mucosa (P < 0.002), it was significantly reduced as compared with normal lip (P < 0.04). Bax expression remained unchanged, and Ki-67 was significantly increased in AC and normal lip as compared with oral mucosa (P < 0.05). CONCLUSION: The results suggest that DNA-damaged cells by UV radiation in AC are eliminated by apoptosis.     

Co-expression of Ki-67 and p53 protein in ameloblastoma and keratocystic odontogenic tumor

Abstract Objectives. The purpose of this study was to evaluate the cell proliferation and p53 protein expression in ameloblastomas (ABs), keratocystic odontogenic tumor (KCOT) and dentigerous cyst (DC). Method. The immunohistochemistry were carried out for Ki-67 and p53 protein expression by using MIB-1 clone and DO-7 clone, respectively, in ABs (n = 23), KCOT (n = 32), DC (n = 30), normal oral mucosa (NOM) (n = 12) and fetal oral mucosa (FOM) (n = 10). Results. Both the Ki-67 LI Labeling index (LI) and p53 LI was significantly higher in ABs than KCOT, DC, NOM and FOM. The Ki-67 LI and p53 LI was significantly higher in KCOT as compared to DC. Ki-67 LI and p53 LI was observed in descending order in ABs, KOCT, FOM, NOM and DC. There was significant correlation between Ki-67 expression and p53 expression in ABs, KCOT, DC and NOM. The densely stained p53 positive cells were noted higher in ABs than KCOT. The very few densely p53 positive cells were noted in DC, NOM and FOM. Conclusion. The results suggest that the p53 protein expression does not necessarily imply an association with malignant disease and/or p53 gene mutation, but a tendency to be expressed in an increasing quantitative and qualitative manner, as the biologic behavior of odontogenic cyst or tumors becomes more aggressive. p53 over-expression may promote cell proliferation in odontogenic lesions. Thus, it can be stipulated that Ki-67 and p53 protein expression can be used as a prognostic marker in odontogenic lesions.     

N-乙酰基转移酶10蛋白和朊蛋白在口腔鳞状细胞癌组织中的表达及相关性研究

目的:检测N-乙酰基转移酶10蛋白(Naa10p)和朊蛋白(PrPc)在口腔鳞状细胞癌(OSCC) 、白斑、口腔正常黏膜中的表达及临床意义。方法:应用免疫组化EnvisionTM法检测OSCC(112例)、白斑(42例)及正常黏膜组织(11例)中Naa10p和PrPc的表达情况,并分析其与临床病理特征相关性。结果:Naa10p和PrPc在OSCC表达最高,白斑次之,正常黏膜组织中表达最低。Naa10p在3种不同组织中的表达两两比较均有显著统计学差异(P<0.05),PrPc分别在白斑和OSCC组织,正常口腔黏膜与OSCC组织中的表达有统计学差异(P<0.05)。Naa10p的表达水平与OSCC的TNM分期、淋巴结转移、组织学分化程度密切相关(P<0.05),与性别、年龄无关。PrPc表达仅与组织学分化程度密切相关(P<0.05)。PrPc在OSCC中的表达强度随组织学分化程度下降而明显升高(P<0.05),而Naa10p的表达强度随组织学分化程度下降而明显下降(P<0.05)。结论:Naa10p和PrPc与OSCC的发生和转移相关。     

The relationship of the histologic grade at the deep invasive front and the expression of Ki-67 antigen and p53 protein in oral squamous cell carcinoma

BACKGROUND: Although many histopathologic characteristics of oral squamous cell carcinoma (O-SCC) have been identified as prognostic factors, accurate, and unequivocal factors have not been clearly identified. The purpose of this study was to evaluate a potential association between the histologic grade of malignancy at the deep invasive front and the expression of Ki-67 antigen and p53 protein in O-SCC. METHODS: The expression of Ki-67 antigen and p53 at the invasive tumor front area of O-SCC was examined by immunohistochemistry of archived tissue from 62 cases. The mean age of patients was 60.7 years (range: 37-89) and the male-female ratio was 1.6:1 (38 men, 24 women). There were 20, 17, 14, and 11 cases classified as stage I to stage IV, respectively. The correlation between the intensity of immunostaining for Ki-67 antigen and p53 and the histologic grade of malignancy at the deep invasive front (invasive front grade, IFG) was analyzed. The expression of Ki-67 antigen and p53 in normal oral epithelia (10 cases) was also investigated. RESULTS: The mean Ki-67 labeling index (LI) in the O-SCC samples was 32.8 +/- 12.0% (n = 62). The mean total score of IFG (IFG score) was 9.1 +/- 2.7 points (n = 62). There was a significant linear correlation between the IFG score and the Ki-67 antigen (gamma = 0.651, R2 = 0.596, P < 0.0001). Of 50 tumors examined, 27 (54.0%) exhibited p53-positive nuclear immunostaining. The staining patterns for Ki-67 antigen and p53 were similar. Both Ki-67-LI and p53-positive status were significantly correlated with the IFG scores. CONCLUSION: The findings of this study demonstrate that overexpression of Ki-67 antigen and p53 at the deep tumor invasive front of O-SCC is associated with histologic grade of malignancy.