Expression of p53 protein correlates with decreased survival in patients with areca quid chewing and smoking-associated oral squamous cell carcinomas in Taiwan

p53 Expression in Leukoplakia and Carcinoma of the Tongue

There is growing interest in assessing multistep carcinogenesis and predicting its course using different molecular markers. TP53 is a tumor suppressor gene and appears to be one of the molecular targets of tobacco-related carcinogens in oral cancer. The present study evaluated the role of p53 expression in patients with leukoplakia and carcinoma of the tongue. p53 expression was studied by immunohistochemistry. All patients with leukoplakia of the tongue were male tobacco users. Nuclear staining of p53 was observed in 79% of those patients. Fifty percent, 25% and 4% of the patients expressed 1+, 2+ and 3+ nuclear staining, respectively. When leukoplakia patients were graded according to histopathology, 67% had hyperplasia and 33% had dysplasia. Nuclear p53 accumulation was 88% in hyperplasia and 62% in dysplasia. In patients with tongue cancer, nuclear accumulation of p53 was seen in only 19% of the tumors, with a staining intensity of 1+ in 13%, 2+ in 2% and 3+ in 4% of the tumors. The prevalence of nuclear p53 positivity (79%) was significantly higher in patients with leukoplakia than in patients with tongue cancer (19%; χ2 = 34.32, r = –0.45, df = 1, p = 0.0001; odds ratio (OR) = 16.66, 95% CI, 5.25–52.86). Therefore, leukoplakia patients who show p53 expression have a higher risk of developing tongue cancer than those who do not show p53 expression. As the percentage of positivity of nuclear p53 was very low, none of the clinicopathological parameters or disease status showed any significant association with it. The interesting finding is that none of the female cancer patients showed nuclear p53 expression. Therefore, p53 accumulation is believed to be an early event in neoplastic progression of the tongue.

Immunohistochemical expression of p53 and its clinicopathological correlation with modified Anneroth's histological grading system

Introduction and Objectives:

Oral squamous cell carcinoma (OSCC) is an epithelial neoplasm generally beginning as focal overgrowth of altered stem cells near the basement membrane, moving upward and laterally, replacing the normal epithelium. Histopathological grading has been used for many decades in an attempt to predict the clinical behavior of oral squamous cell carcinoma. In the present study, Forty biopsies were studied for histological grading and p53 expression. The p53 expression was studied in relation to clinical parameters such as age, sex of patient and site of tumors. Relation between histological grade of malignancy and p53 protein expression was analysed. All cases were classified according to Anneroth's histological malignancy grading system (1987).

Materials and Methods:

40 cases of OSCC were assessed for clinical parameters, Anneroth's histological grading and immunohistochemically stained with p53 protien.

Statistical Analysis:

The results obtained were analyzed using Spearman's Co-relation.

Observations and Results:

The positive expression of p53 was found in 62% of carcinomas studied. Positivity of p53 showed correlation with histological grade of malignancy and with individual parameters like degree of keratinization, nuclear polymorphism, number of mitoses and lymphoplasmacytic infiltration while showed a negative correlation with pattern of invasion.

Conclusion:

Our study showed a significant correlation between parameters of tumor cell population, lymphoplasmacytic infiltration and p53 expression. A significant association between high grade of malignancy and p53 overexpression and insignificant correlation of p53 with age, sex of the patient and site of the tumor was found.

Expression of p53, MDM2, p21, heat shock protein 70, and HPV 16/18 E6 proteins in oral verrucous carcinoma and oral verrucous hyperplasia

BACKGROUND

Oral verrucous hyperplasia is a precancerous lesion of oral verrucous carcinoma.

METHODS

This study used immunohistochemistry to examine the expression of p53, murine double minute 2 (MDM2), p21, heat shock protein 70 (HSP 70), and human papillomavirus (HPV) 16/18 E6 proteins in 48 oral verrucous carcinoma and 30 oral verrucous hyperplasia samples.

RESULTS

The mean labeling indices of p53, MDM2, p21, HSP 70, and HPV 16/18 E6 proteins in oral verrucous carcinoma samples were 21%, 31%, 7%, 17%, and 0.5%, respectively, and those in oral verrucous hyperplasia samples were 19%, 35%, 11%, 14%, and 0.3%, respectively.

CONCLUSIONS

Immunohistochemistry with the above-cited 5 biomarkers could not help differentiate oral verrucous hyperplasia from oral verrucous carcinoma. The low expression of p21 may partially explain abnormal epithelial overgrowth in both verrucous lesions. The pathogenesis of both verrucous lesions may be at least partially attributed to the overexpression of MDM2 protein and moderate expression of HSP 70 protein in both lesions.

Impact of chewing betel-nut (Areca catechu) on liver cirrhosis and hepatocellular carcinoma: a population-based study from an area with a high prevalence of hepatitis B and C infections

BACKGROUND

Chewing betel-nuts (Areca catechu) is carcinogenic but the risk for hepatocellular carcinoma (HCC) and liver cirrhosis (LC) is little considered. Worldwide 600 million people chew betel, including emigrants from palm-growing countries.

OBJECTIVE

We aimed to assess the relationships and dose-response effects of betel chewing on LC and HCC risks, since habit cessation could reduce the increased risks of HCC and LC found in such communities.

SUBJECTS

Screening 60 326 subjects aged 30-79 years in a population-based study in Taiwan identified LC in 588 and HCC in 131 subjects. Demographic features, hepatitis B/C infections, other risk factors and betel chewing were noted. Multiple Cox regression models were used to assess independent relationships, interactions and synergisms between age, betel chewing and hepatitis B/C.

RESULTS

Betel chewing increased LC and HCC risk 4.25-fold (95 % CI 2.9, 6.2) in current chewers and 1.89-fold (95 % CI 1.13, 3.16) in ex-chewers v. never-chewers, with dose effects for quantity, duration and cumulative exposure in chewers. Subjects without hepatitis B/C infections had 5.0-fold (95 % CI 2.87, 9.03) increased risk of LC/HCC v. never-chewers, and betel chewing had an additive synergistic effect on hepatitis B/C-related risks. Risk reduction with betel habit cessation could exceed that expected from immunization programmes for hepatitis B and C.

CONCLUSION

Increased risks of cirrhosis and hepatocellular cancer were found in betel chewers free of hepatitis B/C infection, and these risks were synergistically additive to those of hepatitis B/C infections. Estimated risk reduction from effective anti-betel chewing programmes would be sizeable.

Expression of human telomerase reverse transcriptase (hTERT) protein is significantly associated with the progression, recurrence and prognosis of oral squamous cell carcinoma in Taiwan

This study used an immunohistochemical technique to examine the expression of human telomerase reverse transcriptase (hTERT) protein in 82 specimens of OSCC, 116 specimens of oral epithelial dysplasia (OED), and 21 specimens of normal oral mucosa (NOM). The cytoplasmic and nuclear hTERT staining intensity (SI; 0, no staining; 1, weak; 2, moderate; 3, strong), labeling indices (LIs, defined as the percentage of positive cells in total cells), and labeling scores (LSs, defined as LI x SI) in OSCC, OED, and NOM samples were calculated and compared among groups. The correlation between the cytoplasmic or nuclear hTERT LS in OSCCs and clinicopathological parameters or survival of OSCC patients was analyzed statistically. The mean cytoplasmic hTERT LSs increased significantly from NOM (87+/-17%) through OED (95+/-18%) to OSCC samples (114+/-33%, p=0.000). The mean nuclear hTERT LSs also increased from NOM (80+/-14%) to OED (91+/-20%) and then decreased to OSCC samples (86+/-35%) with no statistically significant difference among the 3 groups. A significant correlation was found between the higher mean cytoplasmic hTERT LSs and OSCCs occurring in male patients (p=0.023), with larger tumor sizes (T3 and T4, p=0.048), with more advanced clinical stages (stages 3 and 4, p=0.033), or from patients with areca quid chewing (p= 0.029), cigarette smoking (p=0.027), or alcohol drinking habit (p=0.025). In addition, OSCC patients with nuclear hTERT LSs greater than 100% were prone to have a higher recurrence rate (p=0.044) and a lower 5-year survival rate (p=0.011). Our results indicate that the increased expression of hTERT protein is an early event in oral carcinogenesis and hTERT may be a biomarker for OSCCs. Measuring the amount of cytoplasmic or nuclear expression of hTERT in OSCC samples may predict the oral cancer progression, recurrence, and prognosis in Taiwan.

Selective reporting biases in cancer prognostic factor studies

BACKGROUND

Nonreported and selectively reported information and the use of different definitions may introduce biases in the literature of prognostic factors. We probed these biases in a meta-analysis of a prognostic factor for head and neck squamous cell cancer (HNSCC) mortality that has drawn wide attention--the status of the tumor suppressor protein TP53.

METHODS

We compared results of meta-analyses that included published data plus unpublished data retrieved from investigators; published data; and only published data indexed with "survival" or "mortality" in MEDLINE/EMBASE, with or without standardized definitions. We also evaluated whether previously published meta-analyses on mortality predictors for various malignancies addressed issues of retrieval and standardized information. All statistical tests were two-sided.

RESULTS

For the 18 studies with 1364 patients that included published and indexed data, we obtained a highly statistically significant association between TP53 status and mortality. When we used the definitions preferred by each publication, the association was stronger (risk ratio [RR] = 1.38, 95% confidence interval [CI] = 1.13 to 1.67; P = .001) than when we standardized definitions (RR = 1.27, 95% CI = 1.06 to 1.53; P = .011). The addition of 13 studies with 1028 subjects that included published but not indexed data reduced the observed association (RR = 1.23, 95% CI = 1.03 to 1.47; P = .02). Finally, when we obtained data from investigators (11 studies with 996 patients) and analyzed it with all other data, statistical significance was lost (RR = 1.16, 95% CI = 0.99 to 1.35; P = .06). Among 18 published meta-analyses of 37 cancer prognostic factors, 13 (72%) did not use standardized definitions and 16 (89%) did not retrieve additional information.

CONCLUSIONS

Selective reporting may spuriously inflate the importance of postulated prognostic factors for various malignancies. We recommend that meta-analyses thereof should maximize retrieval of information and standardize definitions.

Univariate and multivariate analysis of prognostic significance of betel quid chewing in squamous cell carcinoma of buccal mucosa in Taiwan

BACKGROUND AND OBJECTIVES

While betel quid (BQ) chewing is clearly the most avoidable risk factor of squamous cell carcinoma of buccal mucosa (BMSCC), little is known about the influence of this habit on the prognosis of BMSCC.

METHODS

We surveyed 280 patients with BMSCC who were treated during an 8-year period in a cohort study to assess the independent predictive value of pretreatment BQ chewing habit on the prognosis by univariate and multivariate analysis.

RESULTS

We found by univariate analysis that sex, age, clinical stage, smoking, and BQ chewing significantly affected the patients' prognosis and only age, clinical stage, and BQ chewing had significant influence on prognosis by multivariate analysis (P < 0.05). Further analysis revealed that the prognostic effect of BQ chewing changed in a dose- and time-dependent manner. The risk of death was 31.4-fold higher in heavy user (duration >30 years, daily consumption >30 quids, age of start <20 years old) when compared to those who chewed BQ to a milder degree (duration <10 years, daily consumption <15 quids, age of start > or =20 years old ) (P < 0.001).

CONCLUSIONS

Pretreatment BQ chewing habit worsens the prognosis of BMSCC in Taiwan. BQ chewing is a prognostic indicator that can be used in conjunction with clinical staging to help plan the treatment for the patients.

The molecular markers for prognostic evaluation of areca-associated buccal squamous cell carcinoma

BACKGROUND

Buccal squamous cell carcinoma (BSCC) is the most frequently occurring oral cancer in Asians due to the popularity of areca use in this area. The aim of the present study was to evaluate the survival of areca-associated BSCC associated with multiple molecular markers.

METHODS

Using immunohistochemistry, we evaluated the survival of a cohort of 55 patients with BSCC being followed long term, as correlated to the expression of variable markers.

RESULTS

We found that p53, p21, Rb, cyclin D1 (CCD1), MDM2, and gamma-catenin were positive in 81, 60, 70, 31, 88, and 44% of patients, respectively. Subjects with -ve immunoreactivity for CCD1, and +ve immunoreactivity for MDM2 and gamma-catenin had significantly better survival than subjects with the opposite immunoreactive pattern. KAPLAN-meier survival curves confirmed this association.

CONCLUSION

The data indicate that expression of CCD1, MDM2, and gamma-catenin might serve as potential prognostic markers for BSCC in areca-using patients.

Habitual betel quid chewing and risk for hepatocellular carcinoma complicating cirrhosis

This case-control study aimed to assess the independent and interactive role of habitual betel quid chewing and known risk factors for hepatocellular carcinoma (HCC). Subjects enrolled included 210 pairs of sex- and age-matched cirrhotic patients with HCC, patients with cirrhosis alone, and healthy controls. Information on risk factors was obtained through serologic examination of hepatitis B surface antigen (HBsAg) and antibodies to hepatitis C virus (anti-HCV), and a standardized personal interview with a structured questionnaire. Multivariate analysis indicated that betel quid chewing (odds ratio [OR], 5.81; 95% confidence interval [CI], 2.26-14.94); HBsAg (OR, 37.98; 95% CI, 19.65-73.42); and anti-HCV (OR, 47.23; 95% CI, 18.86-118.25) were independent risk factors for HCC when HCC patients were compared with healthy controls. Using patients with cirrhosis alone as a reference group, multivariate analysis indicated that only betel quid chewing (OR, 1.69; 95% CI, 1.04-2.76) and HBsAg (OR, 1.54; 95% CI, l.01-2.37) were independent risk factors for HCC. There was an additive interaction between betel quid chewing and the presence of either HBsAg (synergy index, 5.22) or anti-HCV (synergy index, 1.35). Moreover, a higher risk of HCC was associated with a longer duration of betel quid chewing and a larger amount of betel quid consumed (each p(for trend) < 0.0001). In conclusion, betel quid chewing is an independent risk factor for cirrhotic HCC. There is an additive interaction between betel quid chewing and chronic hepatitis B and/or hepatitis C virus infection.

[An immunohistochemistry study of p53 protein in squamous cell carcinoma of the larynx]

P53 protein detects damages in DNA, stopping the cellular cycle to repair it and stimulates "apoptosis" or programmed death cell when it cannot do it. We present an immunohistochemistry study of 58 squamous cell carcinomas of larynx operated between 1991 and 1996 and in which we detected the overexpression of P53 in 31 cases (53.44%). We did not find a statistic relationship between survival and the detection of P53 protein using Log Rank statistic analysis; the survival media for the wild-type protein cases was 64 months (very similar to native cases).

Prognostic role of p21WAF1 expression in areca quid chewing and smoking-associated oral squamous cell carcinoma in Taiwan

BACKGROUND

Alterations in p21WAF1 protein expression have been observed in a wide variety of human cancers by immunohistochemistry, and both decreased and increased levels of p21WAF1 protein expression have been shown to correlate with poor prognosis.

METHOD

To examine the relation between p21WAF1 protein expression and prognosis in oral squamous cell carcinomas (SCCs), we performed an immunohistochemical study with antip21WAF1 antibody on 43 oral SCCs. Immunostaining results were then correlated with p53 protein levels, clinicopathological parameters of the tumors and overall patient survival.

RESULTS

Of the 43 patients, 31 (72%) had tumors with positive p21WAF1 nuclear staining and 27 (63%) had tumors with p53 nuclear staining. There was no significant correlation between p21WAF1 and p53 protein expressions and both mutant p53-containing oral SCCs overexpressed p21WAF1 protein. In addition, no significant correlation was found between the p21WAF1 expression and the patients' age, sex, oral habit, cancer location, or primary tumor TNM status at the time of initial presentation. The Kaplan-Meier analysis showed a significant correlation between p21WAF1 protein overexpression and poor patient overall survival (P = 0.049). When p53 and p21WAF1 were evaluated together, the 5-year overall survival was lowest in p53(+)-p21WAF1(+) patients and highest in p53(-)-p21WAF1(-) patients (P = 0.057).

CONCLUSION

Combined evaluation of p21WAF1 and p53 expressions may be useful in estimating the prognosis of patients with oral SCCs in Taiwan.

Expression of p53 in oral squamous cell carcinoma and its association with risk habits in southern Thailand

Tobacco smoking and alcohol drinking are the principal factors associated with p53 expression in oral squamous cell carcinomas (OSCC) in the west, whereas betel quid chewing and smokeless tobacco are important factors in the east. Variable results of p53 expression have been reported and it has been proposed that ethnic difference and a variation in the indigenous oral habit may be responsible for the finding. This study, therefore, investigated p53 expression among 106 OSCC patients from a southern Thailand population in which all four risk behaviours, tobacco smoking, alcohol drinking, betel quid chewing and use of smokeless tobacco, are practised. The associations of p53 expression with lifetime exposure to each risk behaviour were explored. Multivariate modelling showed that lifetime exposure to alcohol drinking was significantly positively associated with p53 expression (likelihood ratio P value 0.01). Betel quid chewing and tobacco smoking habit showed a trend of decreasing risk of p53 expression with increased lifetime exposure (OR 0.62, 95% CI 0.39-1.00 and OR 0.50, 95% CI 0.26-0.98, respectively). No significant association was found between p53 expression and clinico-pathological parameters. Further investigations are needed to study (1) the molecular alteration of p53 in each risk habit and (2) other possible pathways of oral carcinogenesis in betel quid- and tobacco smoking-associated OSCC in these group of patients.

Bacterial mutagenicity of some tobacco aromatic nitrogen bases and their mixtures

The first aim was to compare the genotoxicities of two tobacco-specific nitrosamines (TSNA), 4-(methylnitrosamino)-(3-pyridyl)-1-butanone (NNK) and N'-nitrosonornicotine (NNN) in two types of tests, the Salmonella reverse mutation assay (250-2000 microg per plate) and the Mutatox test (up to 1000 microg/ml) using dark mutant M-169 of Vibrio fischeri. The second aim was to assess the effects of single other tobacco chemicals and metabolites (nicotine (NIC), cotinine (COT), trans-3-hydroxycotinine (3HC), cotinine-N-oxide (CNO) and nicotine-N-oxide (NNO)) on the mutagenic responses at relative concentrations observed physiologically. The Salmonella strains were TA100, TA7004, TA7005, and TA7006, all showing missense backmutations that are characteristic of the TSNA. NNN was a direct mutagen to strains TA100, TA7004, and in the Mutatox test, and was not mutagenic in the presence of rat or hamster S9. NNK was mutagenic only in strain TA7004 with rat and hamster S9, but not in TA100, but was directly mutagenic in the Mutatox test. While all the other tobacco chemicals were not mutagenic alone to strains TA100 and TA7004 in the presence and absence of rat or hamster S9, the Mutatox test produced direct mutagenicity for COT, 3HC, and NNO, but not CNO. The latter was mutagenic in the Mutatox test with rat or hamster S9, but only rat S9 was effective for COT, NNO and 3HC. Inhibitory potentiations of NNN by NIC and COT were observed on strain TA7004, and by NIC on strain TA100. There were no interactions on NNK in the presence of S9 for strain TA7004 or TA100. In contrast, a complex inhibition and enhancement behavior occurred in the Mutatox test for each interaction, but no effects were observed for CNO on NNK without S9, and few for NIC on NNK with hamster S9. Compounds which showed no activity alone modulated the genotoxicity of two potent TSNAs in both types of tests.

Betel quid chewing as a risk factor for hepatocellular carcinoma: a case-control study

The role of betel quid chewing in the aetiology of hepatocellular carcinoma (HCC) was evaluated in a case-control study including 263 pairs of age- and sex-matched HCC patients and healthy controls. Serum hepatitis B surface antigen (HBsAg), and antibodies to hepatitis C virus (anti-HCV) were determined, and standardized personal interview conducted using a structured questionnaire. Multivariate analysis indicated that betel quid chewing (odds ratio (OR), 3.49; 95% confidence interval (CI), 1.74-6.96), HBsAg (OR, 16.69; 95% CI, 9.92-28.07), anti-HCV (OR, 38.57; 95% CI, 18.15-81.96), and educational duration of less than 10 years (OR, 1.71; 95% CI, 1.05-2.78) are independent risk factors of HCC. In addition, there was an additive interaction between betel quid chewing and chronic infection with either hepatitis B virus (synergy index, 5.37) or hepatitis C virus (synergy index, 1.66). Moreover, risk on HCC increased as duration of betel quid chewing increased, or amount of betel quid consumed (each P for trend < 0.0001).

Molecular markers predictive of response and prognosis in the patient with advanced squamous cell carcinoma of the head and neck: evolution of a model beyond TNM staging

Advanced head and neck cancer is a disease with poor prognosis. TNM staging is an inadequate prognostic indicator of individual response to evolving multimodal therapies. New markers have been studied in progressively more refined analyses. Even though their role in predicting response and prognosis of head and neck cancer is still under evolution, it is becoming clear that individual markers are inadequate in constructing a prognostically meaningful tumor profile for each patient. Rather the combined study of a number of well-characterized markers acting in unrelated cellular pathways may be much more successful in defining prognostic patient categories of greater utility than traditional TNM staging. Special attention should also be paid to the expression pattern and location of tumor markers within the biopsy specimen as these parameters also appear to influence prognostic significance.

p53 and P-glycoprotein expression are significant prognostic markers in advanced head and neck cancer treated with chemo/radiotherapy

The development of biological markers of response to chemo- and radiotherapy to judge benefit to risk ratios for toxic treatments is still at an experimental stage. Tumour cell death is largely by apoptosis and the p53 gene has a major influence on this. P-glycoprotein (P-gp) accumulation has been correlated with treatment failure in several types of cancer. p53 and P-gp expression were studied in 111 advanced head and neck cancers treated with radiotherapy and up to four courses of synchronous or sequential chemotherapy. The probability of survival at 5 years for patients in the trial as a whole was 27.7%, while the cohort used for this marker project was 29.4%. Among the subjects used for the marker study at the time of analysis, 13 remained disease-free and 18 were alive. Immunohistochemistry was used to assess p53 and P-gp expression; 27/111 (24%) head and neck cancers demonstrated p53/P-gp expression and 33/111 (30%) were both p53- and P-gp- negative. In univariate analysis, both p53 and P-gp expression were associated with reduced disease-free and overall survival. Multivariate analysis revealed tumour size, p53, and P-gp expression as the most powerful pretreatment prognosticators in the study cohort. Long-term follow-up results suggest that p53 and P-gp co-expression predicts the biological behaviour or the outcome following chemo/radiotherapy in advanced head and neck cancer.

Infrequent p53 mutations in patients with areca quid chewing-associated oral squamous cell carcinomas in Taiwan

Mutations in the conserved regions (exons 5-9) of the p53 gene were investigated in 37 untreated human primary oral squamous cell carcinomas (SCCs) using polymerase chain reaction-single strand conformation polymorphism and DNA sequencing analyses. P53 mutations were detected in 2 of 37 (5.4%) oral SCC cases. One tumor sample (case 23) showed a mis-sense point mutation at codon 177, changing CCC to CTC, which resulted in a substitution of proline to leucine in the p53 protein. The other tumor (case 33) had a point mutation at codon 266, changing GGA to AGA and causing a substitution of glycine to arginine in the p53 protein. These two patients with p53 mutations did not have an areca quid chewing habit. These results suggest that mutations in the p53 gene may not play a role in the pathogenesis of human oral SCCs in Taiwan. Recently, we have shown that positive p53 staining was observed in 47 of 81 (58%) cases of oral SCC. The discrepancies between positive p53 protein staining and the low prevalence of p53 mutation in oral SCCs indicate that other mechanism(s) are involved in p53 overexpression.