Early Event In Oral Carcinogenesis Research Articles

Immunohistochemical expression of survivin in oral epithelial dysplasia and different grades of oral squamous cell carcinoma.

Survivin, a member of the inhibitor of apoptosis proteins family, is not detectable in most differentiated normal adult tissues but is expressed in a wide range of cancer tissues. Survivin expression in cancer has been associated with poor prognosis, cancer progression, and drug resistance, and the expression levels correlate with more aggressive disease and a poor clinical outcome. To evaluate and compare the immunoexpression of survivin in the normal oral epithelium (NOE), oral epithelial dysplasia (OED), and different grades of oral squamous cell carcinoma (OSCC). The patterns of survivin immunoexpression and immunoreactivity were assessed in previously diagnosed, paraffin-embedded sections of 10 tissues of NOE and 15 tissues each of OED and the three grades of OSCC (well-, moderately-, and poorly-differentiated). The pattern of survivin expression was recorded as cytoplasmic, nuclear, or both. Survivin immunoreactivity was assessed semi-quantitatively as the immunoreactive score (IRS). Analysis of variance and Tukey-HSD tests were employed for statistical analysis. No immunoreactivity for survivin was evident in the NOE tissues. In the OED tissues, the immunoexpression pattern of survivin was predominantly nuclear in the basal cells, and in the OSCC tissues, cytoplasmic and nuclear. IRS was highest among the moderately- differentiated OSCC, followed by poorly- and well-differentiated OSCC and OED, with a statistically significant difference in the IRS scores between the normal and the study groups. Survivin protein expression may be an important early event in oral carcinogenesis and may predict unfavorable prognosis in OSCC.

RARβ Expression in Keratinocytes from Potentially Malignant Oral Lesions: The Functional Consequences of Re-Expression by De-Methylating Agents.

Simple SummaryPatients may develop white or red patches of the lining of the mouth with an increased risk of developing oral cancer. Treatment with Vitamin A derivatives (retinoids) results in some improvement in these lesions, but this is not maintained, and there are side effects. We know that the cells of the mouth lose cellular receptors for retinoids as these lesions develop, initially by a reversible alteration to the DNA (DNA methylation). Drugs, such as 5-AZA-CdR, which reduce DNA methylation, may restore sensitivity to the effects of retinoids. Treatment of a panel of cells from mouth precancer white patches with retinoids, 5-AZA-CdR and a combination results in varied responses: some cells re-sensitise to retinoids, whereas in others, the main effects on cell division rate and cell lifespan seem related to the effects of 5-AZA-CdR alone. These findings help us to understand the varied responses to retinoids in the clinical setting.Loss of RARβ2 expression by promoter methylation is an early event in oral carcinogenesis. Understanding the mechanisms and consequences of RARβ loss may aid in understanding the disappointing results of retinoid chemoprevention trials. This study aimed to describe the effects of all-trans retinoic acid (ATRA) and the de-methylating agent 5-Aza-2′ deoxycytidine (5-AZA-CdR) on a panel of immortal potentially malignant oral lesion (PMOL) cell cultures. RARβ expression was assessed in PMOL tissues by immunohistochemistry. Cells were treated with ATRA ± 5-AZA-CdR, and the effects on the cell cycle and senescence were assessed. In PMOL tissues, RARβ expression was variable, but lower in biopsies which gave rise to immortal cell cultures. Treatment of iPMOL cells with ATRA resulted in little change in RARβ expression, but the addition of 5-AZA-CdR resulted in significant increases. The effects on the cell cycle and senescence were variable and may be related to 5-AZA-CdR, as this has wider effects on the cell cycle. Overall, the response of iPMOL cells to ATRA and 5-AZA-CdR treatment was variable and is dependent on several factors, including RARβ-promoter methylation. These findings may help to explain the lack of consistent effect of retinoids in PMOLs seen in chemoprevention trials.

An Immunohistochemical Study of HIF-1 Alpha in Oral Epithelial Dysplasia and Oral Squamous Cell Carcinoma.

To evaluate and compare the expression of HIF-1 Alpha (HIF-1α) in oral epithelial dysplasia (OED) and various grades of Oral squamous cell carcinoma (OSCC). 30 cases each of OEDand OSCC were stained with HIF-1α antibody. Quantification of HIF-1α positive cellswas carried out and the data was statistically analysed. The mean % HIF-1α labeling index (HIF-1α LI) increased significantly from mild OED (32.11%), moderate OED (55.07%), to severe OED (64.58%). There was a statistically significant increase in the expression of HIF-1α as grades of OED increased. The mean HIF-1α LI % in well differentiated OSCC was 46.3%, Moderately differentiated OSCC-76.31% and Poorly differentiated OSCC-89.9%. The mean HIF-1α LI was found to increase with increasing grades of OSCC which was statistically significant (P < 0.05). Further a comparison of mean HIF-1α LI in OED with different histologic grades of OSCC by Independent samples t test was performed. We found statistically significant difference between OED and moderately differentiated OSCC and OED and poorly differentiated OSCC (P = 0.000). Progressive increase in expression of HIF-1α was noted from OED to OSCC. It can be postulated that epithelial dysplastic lesions with increased HIF-1α expression are at greater risk of malignant transformation, suggesting that the expression of HIF-1α is an early event in oral carcinogenesis.

Asymmetrical proliferative pattern loss linked to cyclin D1 overexpression in adjacent non-tumour epithelium in oral squamous cell carcinoma

ObjectiveTo evaluate cyclin D1 overexpression in oral squamous cell carcinomas and adjacent non-tumour epithelium as a biomarker of premalignant fields and a risk factor for multiple tumour development. DesignWe studied cyclin D1 expression in 54 patients with 68 oral squamous cell carcinomas plus adjacent non-tumour epithelia characterized as close (n = 58) or distant (n = 41) from the invasion point. Randomized 40x fields were evaluated (4 in tumour tissue and 1 each in close and distant non-tumour epithelium). Expression in non-tumour epithelium was evaluated in basal, parabasal, middle-third and upper-third compartments. ResultsCyclin D1 overexpression was found in both carcinomas and non-tumour epithelia. Nuclear expression in basal and parabasal layers of distant epithelium was significantly increased in patients with multiple tumours (p < 0.001). A significant association between cyclin D1 overexpression in different epithelial layers was found in both close and distant epithelia. A significant association was found between nuclear expressions of cyclin D1 and Ki-67 in the basal layer of distant epithelium (p = 0.02). ConclusionsCyclin D1 overexpression is an early event in oral carcinogenesis linked to loss of the physiological asymmetrical proliferation pattern. Cyclin D1 overexpression in basal and parabasal layers of epithelia distant from the invasion point may act as a potential marker of premalignant fields and multiple tumour development.

The Loss of p16 Expression Worsens the Prognosis of OSCC.

Oral squamous cell carcinoma is the most common neoplasia of the mouth. Downregulation of p16(INK4a) (a cyclin-dependent kinase inhibitor) has been reported for mouth cancer and it is believed that its inactivation is an early event in oral carcinogenesis. The goal of this article is to quantitatively report expression of p16(INK4a) and the state of methylation in oral squamous cell carcinoma, and evaluate its relationship with the clinical and prognostic factors, in addition to setting out a multivariate model that predicts survival. The mean expression of p16(INK4a) was 7.70 (SD=14.07) (F=0.894; P=0.449). According to the semiquantitative analysis, there were statistically significant differences, where 19 cases were negative (<2 %), 11 at initial stages, and 8 at advanced stages (χ(2)=6.016; P<0.05). The methylation of p16(INK4a) was not associated with any of the clinical or pathologic variables. Kaplan-Meier curve showed a better survival for patients in initial stages (40.72 mo) compared to those in advanced stages (28.6 mo) (P<0.01). Survival was also reduced in a statistically significant manner in patients with any degree of dysplasia in the adjacent margin (P<0.05). During univariate Cox regression analysis, it was observed that individuals with relapse had a higher risk (almost 9 times higher) [P<0.001; hazard ratio=8.91; 95% confidence interval (CI), 4.18-19.02]. During the Cox multivariate analysis for each unit of decrease in p16(INK4a), the risk increased by 1.06) (P<0.05; hazard ratio=0.94; 95% CI, 0.89-1.00). p16(INK4a) expression is reduced with advancing tumor stage and its gene silencing is associated with an increased risk of death.

DNA content status using brush biopsy with image cytometry correlated with staging of oral leukoplakia: A preliminary study

Oral leukoplakia (OL) is the best-known potentially malignant disorder of oral cancer. The hypothesis was tested that DNA content abnormality may contribute to risk prediction of malignant potential of OL. All OLs were staged according to a clinicopathologic classification and OL-staging system. DNA content status was investigated in a blinded prospective series of OL using brush biopsy with image cytometry, and examined the correlation of DNA content with the clinicopathologic features and OL-staging system in this preliminary study. Among 65 patients with OL, 27 (41.5%) was identified as DNA content abnormality. The frequency (77.8%) of DNA content abnormality in tongue was higher than that (22.2%) in other oral sites (χ(2) test, P=0.038), and moderate or severe dysplasia had a higher frequency (63.0%) of DNA content abnormality than that (37.0%) of no or mild dysplasia (χ(2) test, P=0.022). Moreover, the odds ratio of DNA content abnormality in high-risk patient group was 5.74-fold (95% confidence interval, 1.81-18.20; P=0.003) increase compared with low-risk patient group. Importantly, the positive correlation between OL-staging system and DNA content status was significant (P=0.018, correlation coefficient=0.292). Our findings showed that DNA content status correlated with OL-staging system, suggesting that DNA content abnormality in OL as detected by image cytometry was an early event in oral carcinogenesis. The further large-scale prospective studies with clinical endpoints are warranted to validate the value of DNA image cytometry.

Immunohistochemical expression of MMP-2 in an experimental progression model of oral cancer

The progression from normal to dysplasia to carcinoma involves series of molecular events. Matrix metalloproteinase-2 (MMP-2), proteolytic enzyme causes the degradation of the basement membrane, which is a primary step in cancer invasion and progression. The aim of this study was to compare the expression of MMP-2 in normal mucosa (NOM), oral epithelial dysplasia (OED) and Oral Squamous cell Carcinoma (OSCC).MMP-2 expression was evaluated immunohistochemically in NOM (n = 10), OED in each of its histological grades (n = 26) and OSCC of the lining mucosa (n = 19). A semi quantita­tive retrospective analysis was carried out in 100 cells in each of 5 different fields at 40x magnification in each case and the proportion of cells expressing MMP-2 were estimated. Suitable positive and negative controls were used for all our analysis. Expression scores of basal cells as well as adjacent stromal cells of OED and tumor cells as well as adjacent stromal cells of OSCC were analyzed. Expression of MMP-2 increased from NOM to OED through different grades to OSCC. Mann Whitney U test for comparison of expression for MMP-2 was statistically significant. However, the comparison for the ex­pression of MMP-2 in mild and moderate dysplasia (p=0.018) as well as moderate and severe dysplasia (p=0.026) was not statistically significant. Increase in the expression of MMP-2 from normal oral mucosa to dysplasia to oral cancer suggests it as an early event in oral carcinogenesis. DOI: http://dx.doi.org/10.3126/jcmc.v4i2.10852 Journal of Chitwan Medical College 2014; 4(2): 3-8

Expression of Gα12 predicts progression and prognosis of oral squamous cell carcinomas in Taiwan

Expression of Gα12 is found to be associated with cancer cell proliferation, migration, invasion, and metastasis. This study used immunohistochemistry to examine the expression of Gα12 protein in 100 specimens of oral squamous cell carcinoma (OSCC), 45 specimens of oral epithelial dysplasia (OED), and 36 specimens of normal oral mucosa (NOM). The mean Gα12 labeling indices (LIs, defined as the percentage of positive cells in total cells) increased significantly from NOM (7 ± 11%) through OED (21 ± 20%) to OSCC samples (53 ± 33%, P < 0.001). The higher mean Gα12 LI was significantly associated with OSCCs with larger tumor size (P = 0.003), positive lymph node metastasis (P = 0.002), or more advanced clinical stages (P = 0.003). Positive lymph node metastasis (P = 0.039) and Gα12 LI > 50% (P = 0.009) were identified as independent unfavorable prognosis factors by multivariate analyses with Cox regression model. Moreover, Kaplan-Meier curve showed that OSCC patients with a Gα12 LI > 50% had a significantly poorer cumulative survival than those with a Gα12 LI ≤ 50% (log-rank test, P = 0.009). Our results showed a stepwise and significant elevation in Gα12 protein expression from NOM through OED to OSCCs, suggesting that overexpression of Gα12 protein may be an early event in oral carcinogenesis and may play a pivotal role in oral cancer development. Moreover, the Gα12 protein can be a biomarker for prediction of the progression of OSCCs and the prognosis of patients with OSCC in Taiwan.

P53 Immunohistochemical Staining Patterns in Benign, Premalignant and Malignant Lesions of the Oral Cavity: A Study of 68 Cases

Context: p53 tumor suppressor gene is a frequent target for mutations in a variety of tumors. The mutated gene is more stable than the normal gene and can be detected by immunohistochemical methods. Aims: 1) To determine the expression of p53 immunohistochemically in a spectrum of benign, premalignant lesions and in various histological grades of oral squamous cell carcinoma 2) To verify if any correlation exists, between the localization and intensity of p53 staining pattern, and the degree of dysplasia. Methods and Material: p53 expression was studied in 68 cases of oral lesions using immunohistochemistry (Dako cytomation). The location and intensity of staining was noted. Suprabasal positivity was considered as abnormal. Results: All the benign lesions and low grade dysplasia were negative or showed only basal positivity. Suprabasal positivity increased from premalignant lesions (50%) to oral carcinomas (73.8%). In the premalignant category, intensity of p53 staining increased with increasing grades of dysplasia. In the malignant category, intensity of staining was stronger in the less differentiated tumors (68.4% vs 47.8%), while positivity was higher in better differentiated tumors (78.3% vs 68.4%). A small percentage of malignant tumors (21.4%) were negative. In 31% cases of SCC, the epithelium adjacent to the tumor which showed just hyperplasia/mild dysplasia on light microscopy, revealed suprabasal positivity. Conclusions: Expression of p53 above the basal layer is an early event in oral carcinogenesis. Stronger staining (increasing grades of dysplasia) had greater risk of progressing into malignancy. p53 positivity is an early indicator of a developing carcinoma preceding morphological tissue alterations.

Loss of the p53/p63 target PERP is an early event in oral carcinogenesis and correlates with higher rate of local relapse

PERP is a p53/p63-regulated gene encoding a desmosomal protein that plays a critical role in cell-cell adhesion and tumor suppression. We evaluated PERP expression in different grades of oral dysplasia (34 cases) and at different stages of invasive squamous cell carcinoma (SCC), and correlated the latter with clinical outcome. A tissue microarray consisting of nondysplastic mucosa, carcinoma in situ, SCC, and nodal metastases from 33 patients with human papilloma virus-negative SCC was stained for PERP and E-cadherin. Complete loss of PERP expression was associated with worse local control in patients with SCC. The 5-year local control rate was 91% for patients with partial PERP loss versus 31% for those with complete loss (P = .01). This is the first study to show that loss of PERP expression correlates with the transition to SCC and with increased local relapse in patients with oral cavity SCC.

P53 immunoprofiling of potentially malignant oral disorders: A case series analysis

p53 tumor suppressor gene which is a frequent target for mutations in a high percentage of oral cancer is regarded as an early event in carcinogenesis. The role of p53 was assessed in potentially malignant oral disorders (PMOD) to ascertain its prognostic significance. Retrospective case series analysis was carried out on 30 paraffin-embedded tissue blocks of confirmed oral leukoplakia with dysplasia. 10 cases of each of mild, moderate, and severe dysplasia were immunohistochemically analyzed for p53 expression. The intensity of staining, intracellular localization, and basal and/or suprabasal distribution were assessed. The intensity of p53 staining and its distribution were analyzed by the Chi-square test. The intracellular localization of p53 in different grades of dysplasia was subjected to one way ANOVA. P<0.05 was considered significant. 21/30 cases of epithelial dysplasia were positive for p53 immunopositivity. Intensity of p53 expression was strong in 12 cases and weak in 9 cases (P<0.05). p53 positivity was confined to basal cells in mild dysplasia, while severe dysplasia showed both basal and suprabasal staining (P<0.05). Nuclear and cytoplasmic staining between and within the groups were F=9.027 and F=6.465 respectively with high significance noted between mild dysplasia and severe dysplasia. Increased p53 expressivity and greater cellular localization with increase in the severity of dysplasia indicated a direct association between the degree of epithelial dysplasia and p53 accretion, which occurs as an early event in oral carcinogenesis.

DAPK promoter hypermethylation in tissues and body fluids of oral precancer patients

Death-associated protein kinase (DAPK) has been suggested as a tumor suppressor gene. A high frequency of DAPK promoter hypermethylation has been noted in head and neck cancers and other solid tumors, and it has been used as a tumor marker in molecular detection strategies. Our aim was to examine DAPK promoter hypermethylation in tissue, blood, and salivary rinse samples of oral precancer patients (OPs) and to explore the potential role in oral carcinogenesis. DAPK hypermethylation was analyzed in 77 OPs and 32 oral squamous cell carcinomas (OSCCs) by real-time quantitative methylation-specific PCR (QMSP). We compared the hypermethylation expression between two groups and analyzed the associations with clinicopathologic parameters. The promoter hypermethylation frequency of DAPK in tissue (46.9%) and blood (52.2%) of OSCCs was significantly higher than those in OPs (19.5%, P = 0.004; 22.4%, P = 0.007, respectively). DAPK promoter hypermethylation expression in blood was correlated with its expression in tissue (r = 0.49, P < 0.000). The OP patients who smoked more than 20 years were found 40.0% tissue DAPK hypermethylation in contrast with 10.7% tissue DAPK hypermethylation in the patients whose smoking duration ≦20 years (P = 0.010). Our results suggest that DAPK hypermethylation is an early event in oral carcinogenesis and blood DAPK hypermethylation might be a potential minimal invasive biomarker for OSCC early detection.

HMLH1 immunoexpression is related to the degree of epithelial dysplasia in oral leukoplakia

hMLH1 is a protein of the mammalian mismatch repair system responsible for genomic stability during repeated duplication. Relation between its altered expression linked to microsatellite instability has also been observed in oral leukoplakias (OL) and squamous cell carcinomas pointing to a possible role of hMLH1 in oral carcinogenesis. To our knowledge, this is the first study evaluating the immunoexpression of hMLH1 in OLs regarding their different degrees of epithelial dysplasia. Sixty-two specimens of OL were classified in four groups: 17 without dysplasia, 19 with mild dysplasia, 16 with moderate dysplasia, and 10 with severe dysplasia. Immunohistochemistry for hMLH1 was performed, and percentage of positive cells was assessed. In the statistical analysis, P values <0.005 were considered significant. hMLH1 immunoexpression showed decreasing indexes from lesions with lower degrees of dysplasia to lesions with more severe dysplasia. Statistical difference was found mainly between suprabasal layers and total indexes. hMLH1 immunoexpression was inversely related to the OL degree of dysplasia. The total epithelial hMLH1 index seems to be of more clinical relevance than the evaluation stratified by layers. Our findings also suggest a role of such alterations in this pathway of DNA repair as an early event in oral carcinogenesis.

Expression of inhibitor of apoptosis family proteins in human oral squamous cell carcinogenesis

The purpose of this study was to determine inhibitor of apoptosis (IAP) expression, its relationship with p53, and epigenetic change in oral carcinogenesis that remain to be elucidated. We measured IAP and p53 expression in 44 oral potentially malignant disorders and their corresponding malignant-transformed oral squamous cell carcinomas (OSCCs), and in 44 other non-transformed oral potentially malignant disorders. IAP and p53 expression in 10 fresh OSCCs, together with epigenetic change of their mutation, were also determined. Normal mucosa did not express IAP/mutated p53. Oral potentially malignant disorders that underwent transformation exhibited high IAPs (>90%) and less-consistent mutated-p53 (34%) expression, whereas transformed OSCCs exhibited high IAP and mutated-p53 expression. Fresh OSCCs exhibited 80% to 100% IAP mRNA expression and 50% protein, mRNA, and p53 mutation expression. Normal tissues revealed DNA methylation of IAP, whereas cancerous tissues overexpressing IAP exhibited hypomethylation. This study showed that IAP expression is an early event in oral carcinogenesis and that epigenetic and genetic pathways are associated with IAP expression in OSCC.

Alteration of extracellular superoxide dismutase expression is associated with an aggressive phenotype of oral squamous-cell carcinoma

Oxidative stress results in damage to cellular structures and has been linked to numerous diseases, including cancer. Extracellular superoxide dismutase (EC-SOD) is a principal enzymatic antioxidant in extracellular space. The purpose of this study was to determine whether the expression of EC-SOD protein is altered in the carcinogenetic process of oral squamous-cell carcinoma (OSCC). Immunohistochemical analysis was carried out in matched normal and tumour specimens collected from 58 OSCCs and 20 oral premalignant lesions (OPLs). Correlations between the EC-SOD expression levels and clinicopathological features of OSCC patients were evaluated by Fisher's exact test. Although EC-SOD protein was consistently expressed on the plasma membrane of cells in normal tissues, plasma membranous EC-SOD expression was lost in almost all the OSCC specimens examined (98%). Instead, positive EC-SOD expression was detected in the cytoplasmic compartments of cancerous cells in both OPLs (65%) and OSCCs (52%), together with a high incidence of lymph node metastasis (p=0.0397). These results suggest that the dysregulation of EC-SOD protein expression is a frequently occuring and early event in oral carcinogenesis, and that cytoplasmic EC-SOD may contribute to the increased aggressiveness of OSCC.

Chromosomal numerical aberrations in apparently normal oral mucosa of heavy smokers affected by lung cancer

Cigarette smoke creates a field of injury in the epithelial lining of the entire respiratory tract causing an increased risk for the development of malignant lesions. It is conceivable, therefore, that early genetic alterations, can be detected in oral mucosa of heavy smokers mainly those affected by lung cancer. As aneuploidy was shown to be an early event in oral carcinogenesis, we aimed to investigate the prevalence of aneuploid cells (ACs) in samples obtained from apparently normal looking oral mucosa of heavy smokers affected by lung cancer (LC). Two brush samples were collected from the oral mucosa of 152 subjects; 31 heavy smokers with LC, 59 heavy smokers without LC and 62 never-smokers. The samples were simultaneously analyzed for morphology and fluorescent in situ hybridization (FISH) using chromosomes 2 and 8 centromeric probes. Over 2% ACs were found in 23% of heavy smokers with LC compared to 12% in heavy smokers without LC and 5% of the never-smokers group (P=0.015). A trend was also noticed when comparing the group of heavy smokers without LC with the never-smokers (P=0.198). We conclude that heavy smokers harbour detectable chromosomal numerical aberrations in oral epithelial cells of normal looking mucosa. These aberrations are more frequently found in heavy smokers affected by LC.

DNA aneuploidy and dysplasia in oral potentially malignant disorders: Association with cigarette smoking and site

To date there are still no reliable biomarkers for oral potentially malignant disorders (PMDs) to predict the risk of progression to squamous cell carcinoma (SCC). Within a prospective clinical trial of patients with PMDs, DNA content flow cytometry (DNA FCM) was evaluated for 60 PMDs using fresh samples obtained by a dermatological curette. There were 6/42 PMDs without dysplasia, but with DNA aneuploidy, versus 8/18 with both dysplasia and aneuploidy (p=0.02). When the tongue and the buccal mucosa, the two most common sites in the present series of cases were compared, dysplastic PMDs were mainly located on the tongue (p=0.01). Tobacco smokers, who preferentially developed PMDs in the buccal mucosa at a younger age than non-smokers (p=0.002), had fewer dysplastic PMDs than did non-smokers (p=0.01). Dysplasia was significantly linked to DNA aneuploidy (p=0.03) in smokers. The present data suggest that aneuploidy is an early event in oral carcinogenesis and that the influence of tobacco varies according to subsite and patient age. When DNA FCM of PMD samples are obtained by curette scraping, extensive areas can be covered with a minimally invasive, rapid, inexpensive procedure. Moreover DNA FCM of these samples appears easy amenable to routine analysis. Further research on larger numbers of PMDs should be carried out to determine whether DNA FCM plays a role in the prediction of risk of PMD transformation.

Decreased expression of Ep‐CAM protein is significantly associated with the progression and prognosis of oral squamous cell carcinomas in Taiwan

The epithelial cell adhesion molecule (Ep-CAM) is involved in cell signaling, migration, proliferation, cell-cycle regulation, and cancer metastasis. This study used an immunohistochemical technique to examine the expression of Ep-CAM protein in 84 specimens of oral squamous cell carcinoma (OSCC), 98 specimens of oral epithelial dysplasia (OED, 31 mild, 41 moderate, and 26 severe OED cases), and 15 specimens of normal oral mucosa (NOM). We found that the mean Ep-CAM labeling indices (LIs) decreased significantly from NOM (80 +/- 18%) and mild OED (76 +/- 14%) through moderate OED (66 +/- 22%) and severe OED (55 +/- 20%) to OSCC samples (46 +/- 16%, P < 0.001). A significant correlation was found between the lower mean Ep-CAM LI and OSCCs with larger tumor size (P = 0.003), positive lymph node metastasis (P = 0.022), more advanced clinical stages (P < 0.001), cancer recurrence (P = 0.021), or extracapsular spread of lymph node (P = 0.015). However, only Ep-CAM LI < 50% (P < 0.0001) was identified as an independent unfavorable prognosis factor by multivariate analyses with Cox proportional hazard regression model. Kaplan-Meier curve showed that OSCC patients with an Ep-CAM LI < 50% had a significantly poorer cumulative survival than those with an Ep-CAM LI > or = 50% (P < 0.00001, log-rank test). We conclude that the decreased expression of Ep-CAM protein is an early event in oral carcinogenesis. The Ep-CAM LI in OSCC samples can predict the progression of OSCCs and the survival of OSCC patients.

Expression of RCAS1 is significantly associated with the progression and prognosis of oral squamous cell carcinomas in Taiwan

This study used an immunohistochemical technique to examine the expression of receptor-binding cancer antigen expressed on SiSo cells (RCAS1) in 84 specimens of oral squamous cell carcinoma (OSCC), 106 specimens of oral epithelial dysplasia (OED, 32 mild, 44 moderate, and 30 severe OED cases), and 20 specimens of normal oral mucosa (NOM). We found that the mean RCAS1 labeling indices (LIs) increased significantly from NOM (12+/-5%) through mild OED (31+/-13%), moderate OED (44+/-17%), and severe OED (56+/-18%) to OSCC samples (68+/-20%, p<0.001). A significant correlation was found between the higher mean RCAS1 LI and OSCCs with larger tumor size (p=0.001), positive lymph node metastasis (p<0.001), or more advanced clinical stages (p<0.001). Positive lymph node metastasis (p=0.0073) and RCAS1 LI > or = 60% (p=0.048) were identified as independent unfavorable prognosis factors by multivariate analyses with Cox regression model. Kaplan-Meier curve showed that OSCC patients with a RCAS1 LI > ot = 60% had a significantly poorer cumulative survival than those with a RCAS1 LI<60% (log-rank test, p=0.0113). We conclude that the expression of RCAS1 is an early event in oral carcinogenesis. The RCAS1 LI in OSCC samples can predict the progression of OSCCs and the survival of OSCC patients.

Expression of hypoxia‐inducible factor‐1α is significantly associated with the progression and prognosis of oral squamous cell carcinomas in Taiwan

Background: Overexpression of hypoxia‐inducible factor‐1α (HIF‐1α) has been found to be significantly associated with the tumor invasion, lymph node metastasis, clinical stage, and prognosis of a variety of human cancers.Methods: This study examined the expression of HIF‐1α in 57 specimens of oral squamous cell carcinoma (OSCC), 41 specimens of oral epithelial dysplasia (OED, 12 mild, 17 moderate, and 12 severe OED cases), and 14 specimens of normal oral mucosa (NOM) by immunohistochemistry.Results: We found that the mean nuclear HIF‐1α labeling indices (LIs) increased significantly from NOM (9 ± 6%) through mild OED (25 ± 18%), moderate OED (41 ± 27%), and severe OED (42 ± 22%) to OSCC samples (55 ± 23%, P &lt; 0.001). A significant correlation was found between the higher mean nuclear HIF‐1α LI and OSCCs with larger tumor size (P &lt; 0.001), regional lymph node metastasis (P &lt; 0.001), or more advanced clinical stages (P &lt; 0.001). Only larger tumor size (P = 0.002) and nuclear HIF‐1α LI ≥ 60% (P = 0.048) were identified as independent unfavorable prognosis factor by multivariate analyses with Cox regression model. Kaplan–Meier curve showed that OSCC patients with a nuclear HIF‐1α LI ≥ 60% had a significantly poorer cumulative survival than those with a nuclear HIF‐1α LI &lt; 60% (log‐rank test, P = 0.022).Conclusions: We conclude that the expression of HIF‐1α is an early event in oral carcinogenesis. The nuclear HIF‐1α LI in OSCC samples can predict the progression of OSCCs and the survival of OSCC patients.