Lack of type-specific concordance between human papillomavirus (HPV) serology and HPV DNA detection in the uterine cervix and oral mucosa.

There is limited knowledge about longitudinal genotype-specific concordance between human papillomavirus (HPV) serology and co-existent presence of HPV DNA in the uterine cervix. The role of oral HPV infections in inducing serological response is unclear, as is the effect of HPV antibodies on the outcome of oral HPV infections. The present study is part of the Finnish Family HPV Study designed to evaluate dynamics of HPV infections within families. Here, we correlated the point prevalence of HPV6, 11, 16, 18 and 45 antibodies and concomitant genotype-specific HPV DNA detection in cervical and oral samples of 323 mothers during their 3 year (mean 37.5 months) follow-up. The mean age of these pregnant mothers at enrolment (third trimester) was 25.5 years. HPV antibodies were analysed with multiplex HPV serology and HPV genotyping was performed using a Multimetrix kit (Progen Biotechnik). There was no concordance between cervical DNA detection and co-existent seropositivity, and the same was true even in samples taken 12 months apart. Women who cleared their cervical HPV16 infection had the highest HPV16 antibody levels, whereas those who acquired incident HPV16 infections had the lowest antibody levels. Neither the presence nor the dynamics of oral HPV DNA had any correlation with HPV serology.

Fas/CD95 promoter polymorphism gene and its relationship with cervical carcinoma.

OBJECTIVE: Apoptosis is an important fail-safe control in human papillomavirus (HPV)-associated carcinogenesis. We tested the hypothesis that the A/G polymorphism at -670 of Fas promoter is associated with an increased risk for cervical cancer, using a matched case-control setting. METHODS: The material in this case-control study consisted of 91 patients with cervical carcinoma and 176 population-based control subjects, recruited between 2002 and 2004; all the ethnic Brazilian women had histologically confirmed cervical carcinoma. Control subjects were age-matched; healthy women who were selected following a negative cervical cytology and normal colposcopy. Fas genotyping was performed using a PCR-RFLP technique. RESULTS: No significant difference existed in the distribution of the Fas polymorphisms (wild, heterozygous, mutant) between the cases and controls. The heterozygous (OR: 4.85, 95% CI: 1.1-22.6) genotypes among the younger (< 48 yrs) cancer patients were almost 5-fold increased, as compared with the wild type. No such increase was observed among the patients older than 48 years. CONCLUSIONS: Our data suggest that 670A/G polymorphism in the promoter region of the death receptor Fas is associated with an increased risk of cervical cancer among Brazilian women under 48 years. The mechanisms would be the inhibition of apoptosis by Fas -670G allele-mediated down-regulation of Fas transcription.

p16(INK4a) Expression does not predict the outcome of cervical intraepithelial neoplasia grade 2.

Spontaneous regression of cervical intraepithelial neoplasia grade 2 (CIN2) lesions has been recognized since 1955, but predictors of this are poorly understood. Among the predictive markers studied, p16(INK4a) has been suggested to be of some value in monitoring the diagnosis of CIN2. In this clinical trial, 90 Brazilian women, diagnosed to CIN2 and high-risk human papillomavirus infection, were randomized into two groups of equal size: 45 women whose lesions were excised and 45 women subjected to prospective follow-up at 3-month intervals at least for 1 year (mean 6.8 months). p16(INK4a) expression was analyzed in paraffin-embedded sections using immunohistochemical staining. Among the 45 women in the follow-up group, 42% experienced spontaneous regression, 11% showed persistence, 22% progressed to CIN3, and 20% had partial regression to CIN1 or ASCUS (atypical squamous cell undetermined signifiance). p16(INK4a) expression was detected in 68.9% of the patients. In univariate survival (Cox) analysis, no significant difference in regression was obtained between p16(INK4a)-negative and -positive CIN2 lesions (adjusted HR = 1.1; 95% CI 0.6-2.0). In conclusion, p16(INK4a) expression could be useful in the diagnosis of CIN2. However, it failed to predict the outcome of CIN2. Because of its high spontaneous regression rate, follow-up could be considered as a management option of CIN2 in young and compliant women.

Interleukin-6 polymorphisms and the risk of cervical cancer.

Recent data implicate that cytokine gene polymorphisms are important in pathogenesis of various neoplastic and nonneoplastic human diseases, and it was recently suggested that polymorphisms in interleukin (IL)-6 might increase the risk of gynecological malignancies, including cervical carcinomas. The aim of this case-control study is to compare the IL-6 polymorphisms in cervical cancer patients and healthy controls and to assess whether any of these polymorphisms would increase the risk of developing cervical cancer. The material in this case-control study consists of 56 patients with cervical carcinoma and 253 population-based control subjects, all ethnic Brazilian women. Control subjects were cancer-free women, following a negative cervical cytology and colposcopy. IL-6 genotyping was performed using a polymerase chain reaction-based restriction fragment length polymorphism. Distribution of the GG, GC, and CC genotypes in cases and controls was significantly different (P= 0.033). Compared with the GG genotype as reference, the adjusted odds ratio for the combined GC and CC genotypes in cancer patients was 1.90 (95% confidence interval, 1.1-3.4). These data suggest that women carrying at least one C genotype in their IL-6 promoter region (-174G-->C) are at higher risk of developing cervical cancer.

Prevalence of genital human papillomavirus infections established using different diagnostic techniques among males attending a urological clinic.

OBJECTIVE: To compare the accuracy of different diagnostic methods and their use in estimating the prevalence of genital human papillomavirus (HPV) infections in males attending a urological clinic. MATERIAL AND METHODS: The study population was derived from a series of 1,153 consecutive males attending a urological clinic in São Paulo between January 1996 and November 1998. Of these 1,153 males, 334 had clinically suspected genital HPV infection and comprised the study cohort. The diagnostic methods used included peniscopy, directed biopsy and HPV detection by means of the Hybrid Capture 2 (HC) assay for both oncogenic and non-oncogenic HPV types. RESULTS: Peniscopy was performed for 297 males, positive results being reported in 237 cases (79.8%). Directed biopsy was performed in 188 males, and histology suggested HPV in 140 of these cases (74.5%). HC confirmed the presence of HPV in only 35.2% of the histologically HPV-suggestive cases. Peniscopy has good sensitivity for identifying male carriers of genital HPV. However, the technique has an inherent low specificity, limiting its usefulness to the correct identification of those who never present with HPV infection. Characteristic histological alterations are useful in suggesting HPV infection, but their correlation with HPV detection using HC is not particularly good. CONCLUSIONS: These data suggest that both histology and peniscopy have low specificity in detecting male genital HPV. Accurate diagnosis of HPV infection can be confirmed by molecular detection methods only. Histology, however, plays an important role in the differential diagnosis. An appropriate diagnostic protocol for male genital HPV infections in a urological clinic should include peniscopy, histology and molecular diagnostic tools (HC or polymerase chain reaction).

Early integration of high copy HPV16 detectable in women with normal and low grade cervical cytology and histology.

BACKGROUND: Integration of human papillomavirus (HPV) DNA has been considered a late event in cervical carcinogenesis. However, integrated forms of HPV were recently detected in cancer precursor lesions using a new real time polymerase chain reaction (PCR) to detect the deletions at the 3362-3443 region of HPV16 E2 OBJECTIVE: To study the frequency of HPV16 DNA integration in cervical lesions and compare the sensitivity of an additional upstream region of the E2 ORF (2962-3138) in detecting HPV integration. METHODS: Using the TaqMan based PCR, HPV16 positive DNA samples were analysed in 164 cervical scrapings from women participating in a multicentre screening trial. Biopsy confirmation was available in 62 cases. RESULTS: Primers targeting the 3362-3443 region detected the majority of E2 deletions. In only 23% of the samples was the E2 upstream region equal or better target than the 3362-3443 region. Mixed (episomal/integrated) pattern was the most prevalent physical state of HPV16, also present in PAP smears with normal morphology. Pure integrated form was most prevalent in HSIL and cancer lesions, but also detectable in low grade abnormalities (NSIL, ASC-US, LSIL). Women with only integrated HPV16 were almost 10 years older than those with episomal HPV16. Viral load of integrated HPV16 was related to cytological abnormality (p = 0.003) but not to histology. CONCLUSIONS: Integrated HPV16 is present in low grade cervical lesions, mostly mixed with the episomal form. Women with the pure integrated form of HPV16 are older than those with the other forms.

Clearance of high-risk human papillomavirus (HPV) DNA and PAP smear abnormalities in a cohort of women subjected to HPV screening in the New Independent States of the former Soviet Union (the NIS cohort study).

BACKGROUND: We analysed the temporal relationships of the clearance of human papillomavirus (HPV) DNA and cytological abnormalities in women participating in a screening study in three NIS countries. METHODS: The 274 patients included in this analysis were prospectively followed-up for 21.6 months (range: 0.5-42.9). All 274 women had abnormal PAP test (ASC-US or higher) and high-risk HPV-positive test (HCII) at baseline. Two groups were compared: 132 women who cleared both tests (Group 1), and 142 women who cleared either HPV or abnormal PAP test (Group 2). The first clearance during the follow-up, and the last visit clearance were modeled using life-table techniques, and the predictive factors were analysed using univariate (Kaplan-Meier) and multivariate (Cox) survival analysis. RESULTS: There was no difference in the mean clearance time for the abnormal PAP test (14.4 months; 0.7-40.5 and 12.6 months; 0.5-35.0) and high-risk HPV DNA (12.67 months; 0.6-33.5 and 10.8 months; 0.7-33.4) in Group 1 and Group 2 (Mann-Whitney: P = 0.107 and P = 0.082, respectively). Clearance times for HPV DNA and abnormal PAP test did not deviate from each other in either groups (Wilcoxon: P = 0.063 and P = 0.088). The monthly clearance rates for the abnormal PAP test are 1.32 and 1.38%, and those for the HPV DNA 1.62 and 1.61%, in Groups 1 and 2, respectively. Of the factors predicting the last visit clearance, the issues related to smoking are of particular interest. CONCLUSIONS: The clearance of high-risk HPV type and abnormal PAP test shows a close temporal relationship, the former preceding the latter, however, by an interval of 1.0-2.0 months.

Immunohistochemistry in assessment of molecular pathogenesis of cervical carcinogenesis.

Concerning the prediction of HPV-associated cervical disease, several importance issues are related both to the management of women with diagnosed CIN and those with cervical cancer. Oncogenic HPVs are capable of contributing to the development of malignant phenotype by several different mechanisms, most of which seem to be closely interrelated. Because of the fact that these molecular interactions are mediated by proteins, the logical strategy to dissect the complex molecular pathways is to study the functions of these proteins, utilising the capabilities of immunohistochemistry (IHC). IHC offers practically unlimited possibilities to study any target molecules, against which a monoclonal or polyclonal antibody can be raised. This review describes the IHC-based strategies used by this author to assess the molecular pathogenesis of cervical cancer and its precursors in a number of large-scale prospective cohort studies conducted during the past 25 years. In the ongoing HPV-PathogenISS study, 13 different markers are being tested to evaluate their predictive value in distinct viral events, e.g. persistence or clearance of high-risk HPV in women treated for CIN. Apart from getting new insights into the molecular pathogenesis of HPV-associated cervical carcinogenesis, we anticipate the disclosure of individual markers, a set of markers, or an expression profile of any such marker sets that would be of clinical value as predictors of disease outcome in cervical carcinogenesis.

Prognostic value of P53 codon 72 polymorphism in invasive cervical cancer in Brazil.

OBJECTIVE: The prognostic value of p53 codon72 polymorphism was analyzed in Brazilian women with cervical cancer. METHODS: The present study consists of 148 women diagnosed and treated for invasive cervical carcinoma (FIGO stages Ib-IIIb) between 1992 and 2002. Demonstration of p53 polymorphism was performed in DNA extracted from paraffin-embedded sections using the polymerase chain reaction (PCR). RESULTS: Among the 148 women, arg/arg was found in 99 (67%) and, arg/pro in 49 (33%). The overall survival (OS) curves (univariate) were different between arg/arg and arg/pro patients (P = 0.01). There was slightly increased risk of death for arg/arg patients (crude HR 2.2 CI 95% 1.2-4.0), which was not confounded by FIGO stages (adjusted HR 2.4 CI 95% 1.3-4.3). For disease-free survival (DFS), two situations were considered: (1) 124 women who received any treatment, and (2) 118 who received FIGO-recommended treatment. In the first group, 59% of arg/arg patients presented recurrence as compared to 32% in the arg/pro group (P = 0.02), whereas in the second group, 61% of the arg/arg and 34% arg/pro showed recurrence (P = 0.04). The risk of recurrence adjusted by FIGO stage for the 124 patients was 2.4 (CI 95% 1.0-3.7) and for the 118 it was 1.9 (CI 95% 1.0-3.4). These adjusted models showed no confounding and no interaction. CONCLUSIONS: Despite the prognostic significance of p53 polymorphism in univariate survival analysis, there was no or only marginal evidence on the independent prognostic value of p53arg/arg in multivariate analysis. The more ominous prognosis of the homozygous (arg/arg) patients was explained by the primary treatment, independent on the FIGO stage.

Expression of p53, c-erbB-2, Ki-67, and CD34 in granulosa cell tumor of the ovary.

The purpose of this study is to investigate the expression of p53, c-erbB-2, Ki-67, and angiogenic activity and their correlation with the clinicopathologic characteristics in a series of granulosa cell tumors of the ovary (GCTO). Eighteen GCTO cases assisted at the Department of Obstetrics and Gynecology, School of Medical Science, UNICAMP, after diagnostic confirmation by three pathologists, were submitted to immunohistochemistry for assessment of p53, c-erbB-2, Ki-67, and CD34 expressions. The mean tumor size was 13 cm (range: 4-30 cm). Six (33%) cases presented with extraovarian disease. Thirteen (72%) cases presented some solid diffuse or sarcomatoid pattern and six (33%) moderate or strong atypia. Fourteen cases presented

HPV infections in benign and malignant sinonasal lesions.

This review updates the evidence that the human papillomavirus (HPV) is involved in the development of benign and malignant sinonasal lesions. Since the early 1980s, when evidence was provided on the possible involvement of HPV in the aetiology of both benign respiratory papillomas and squamous cell carcinomas, a substantial number of studies have explored this issue. To date, 33.3% of sinonasal papillomas and 21.7% of sinonasal carcinomas analysed have been shown to be positive for HPV. Many elements of the data parallel the observations made in HPV lesions at other mucosal sites, such as malignant transformation and frequent recurrence after radical treatment; the fact that low risk HPV types 6 and 11 are usually confined to benign lesions, whereas the reverse is true for the oncogenic HPV types 16 and 18; and the presence of squamo-columnar junctions and squamous cell metaplasia in the sinonasal system. The discrepancies reported by several studies might result in part from technical reasons, but it is also possible that sinonasal lesions have a heterogeneous aetiology (HPV related and non-related) and/or that some novel (yet unidentified) HPV types exist in these lesions, which are detected by some studies but not by others.

HPV infections and lung cancer.

Because of the major clinical impact of bronchial cancer worldwide, the possibility that human papillomavirus (HPV) contributes to its pathogenesis as a co-carcinogen is an intriguing one. Bronchial squamous cell carcinoma develops through well defined precursor lesions, often at the sites of squamous metaplasia. Benign squamous cell papillomas are rare but HPV DNA has been found in almost half of those studied, implicating a causal association. In invasive bronchial cancer, morphological changes seen in HPV lesions elsewhere are often seen. HPV DNA has been detected in 21.7% of the 2,468 bronchial carcinomas analysed to date and the same high risk types implicated in other squamous cell cancers have been identified. Clearly, more effort should be focused on assessing the role of HPV in bronchial carcinogenesis, by analysing the synergistic effects of carcinogenic agents (cigarette smoke, radiation, asbestos, etc) and HPV in different experimental settings.

P53 and Bcl-2 as prognostic predictors in epithelial ovarian cancer.

The study was designed to evaluate the prognostic importance of clinical and pathologic variables with p53 and Bcl-2 in epithelial ovarian cancer using multivariate analysis. Tumor tissues from 90 patients were analyzed immunohistochemically for p53 and Bcl-2 expression. Hazard ratios were calculated in univariate and multivariate survival analyses. Forty-two (47%) were considered positive for p53 expression and 18 (20%) were positive for Bcl-2. Positive expression for p53 was less frequent in patients in FIGO stage I (22%). Positive staining for Bcl-2 correlated significantly with the histologic type (P < 0.01). No direct correlations could be demonstrated between p53 and Bcl-2 expression and age or histologic grade. In univariate analysis, p53 and Bcl-2 expression were not significantly correlated with overall survival, disease-free survival, or progression time. FIGO stage III and IV and residual disease > or =2 cm3 after first surgery were significantly correlated with poor outcome in univariate analysis. FIGO stage retained their independent prognostic value in multivariate analysis. Neither p53 nor Bcl-2 had any significant influence on outcome in multivariate survival analysis. FIGO stage proved to be the only significant independent prognostic factor in epithelial ovarian cancer, although residual disease remains correlated with disease-free survival.

HPV infections and oesophageal cancer.

The first reports suggesting an involvement of human papillomavirus (HPV) in the development of both benign and malignant squamous cell tumours of the oesophagus date back to 1982. Since then, a substantial amount of literature has accumulated on this subject, summarised in this review. To date, 239 oesophageal squamous cell papillomas have been analysed in 29 separate studies using different HPV detection methods, with HPV being detected in 51 (21.3%) cases. Many more squamous cell carcinomas have been analysed: of the 1485 squamous cell carcinomas analysed by in situ hybridisation, 22.9% were positive for HPV DNA, as were 15.2% of the 2020 cases tested by the polymerase chain reaction. In addition, evidence derived from large scale serological studies, animal experiments, and in vitro studies is discussed in the light of the highly variable geographical incidence rates of oesophageal carcinoma worldwide. It may be that the (multifactorial) aetiology of oesophageal cancer differs greatly between those geographical areas with a low risk and those with a high risk for this disease. Oncogenic HPV types seem to play an important causal role, particularly in high risk areas.

P53 expression as a predictor of recurrence in cervical squamous cell carcinoma.

P53 protein function is frequently down-regulated in cervical cancer by complexing with human papillomavirus (HPV) E6 protein, leading to degradation of p53, genomic instability, and mutations. Results are controversial, however, on the prognostic value of p53 protein expression in cervical cancer. In this study, a cohort of 220 Brazilian women with FIGO stage IB-III cervical squamous cell carcinoma (SCC), followed for 5 years, was analyzed for p53 protein expression using immunohistochemistry. The disease-free survival (DFS) and relapse rate were analyzed using univariate (Kaplan-Meier) and multivariable (Cox's proportional hazards model) survival analyses. P53 protein expression was detected in 35% of the patients, including 21% in stage I, 28% in stage II and 51% in stage III of disease. Of 220 women, only 116 completed one of the treatment options standardized by FIGO within 120 days. There was a higher risk of relapse in stage II and III disease, that was not modified by p53 positivity; HR 3.0 (1.3-6.5) to stage II and HR 4.0 (1.9-8.5) to stage III. The multivariate analysis evidenced that p53 expression is not an independent factor exceeding the power of FIGO stage as the single most important determinant of the hazards for disease relapse.

c-Myc protein expression is not an independent prognostic predictor in cervical squamous cell carcinoma.

The c-myc protein is known to regulate the cell cycle, and its down-regulation can lead to cell death by apoptosis. The role of c-myc protein as an independent prognostic determinant in cervical cancer is controversial. In the present study, a cohort of 220 Brazilian women (mean age 53.4 years) with FIGO stage I, II and III (21, 28 and 51%, respectively) cervical squamous cell carcinomas was analyzed for c-myc protein expression using immunohistochemistry. The disease-free survival and relapse-rate were analyzed using univariate (Kaplan-Meier) survival analysis for 116 women who completed the standard FIGO treatment and were followed up for 5 years. Positive c-myc staining was detected in 40% of carcinomas, 29% being grade 1, 9% grade 2, and 2% grade 3. The distribution of positive c-myc according to FIGO stage was 19% (17 women) in stage I, 33% (29) in stage II, and 48% (43) in stage III of disease. During the 60-month follow-up, disease-free survival in univariate (Kaplan-Meier) survival analysis (116 women) was lower for women with c-myc-positive tumors, i.e., 60.5, 47.5 and 36.6% at 12, 36, and 60 months, respectively (not significant). The present data suggest that immunohistochemical demonstration of c-myc does not possess any prognostic value independent of FIGO stage, and as such is unlikely to be a useful prognostic marker in cervical squamous cell carcinoma.

C-Myc protein expression is not an independent prognostic predictor in cervical squamous cell carcinoma

The c-myc protein is known to regulate the cell cycle, and its down-regulation can lead to cell death by apoptosis. The role of c-myc protein as an independent prognostic determinant in cervical cancer is controversial. In the present study, a cohort of 220 Brazilian women (mean age 53.4 years) with FIGO stage I, II and III (21, 28 and 51 percent, respectively) cervical squamous cell carcinomas was analyzed for c-myc protein expression using immunohistochemistry. The disease-free survival and relapse-rate were analyzed using univariate (Kaplan-Meier) survival analysis for 116 women who completed the standard FIGO treatment and were followed up for 5 years. Positive c-myc staining was detected in 40 percent of carcinomas, 29 percent being grade 1, 9 percent grade 2, and 2 percent grade 3. The distribution of positive c-myc according to FIGO stage was 19 percent (17 women) in stage I, 33 percent (29) in stage II, and 48 percent (43) in stage III of disease. During the 60-month follow-up, disease-free survival in univariate (Kaplan-Meier) survival analysis (116 women) was lower for women with c-myc-positive tumors, i.e., 60.5, 47.5 and 36.6 percent at 12, 36, and 60 months, respectively (not significant). The present data suggest that immunohistochemical demonstration of c-myc does not possess any prognostic value independent of FIGO stage, and as such is unlikely to be a useful prognostic marker in cervical squamous cell carcinoma

Value of morphological criteria in diagnosing cervical HPV lesions confirmed by in situ hybridization and hybrid capture assay.

The present study evaluated the value of morphological criteria (binucleation, multinucleation, koilocytosis, spindle koilocytes, abnormal mitosis and dyskeratosis) in the diagnosis of cervical human papillomavirus (HPV) lesions confirmed by in situ hybridization (ISH) and hybrid capture (HC) assay. Colposcopic punch biopsies from a series of 138 women with abnormal Pap smears were examined on light microscopy and in situ hybridization (DAKO widespectrum cocktail probe) for HPV-induced morphological changes and HPV DNA, respectively. Cervical swabs were analyzed for HPV DNA of the oncogenic types using Hybrid Capture. CIN 2 and CIN 3 were found in 44 biopsies, CIN 1 in 62, and no evidence of HPV in 32 cases. HPV was detected by ISH in 51/138 (37%) cases and by HC in 66/138 (48%) lesions. With both tests, HPV DNA detection increased parallel with lesion severity, up to 70% and 59% in CIN 2/3 by HC and ISH, respectively OR 4.6 (1.7-12.1) and 10.1 (3.0-33.8). Among the histological criteria, multinucleation, binucleation and abnormal mitoses were significantly associated with HPV DNA detection. Multinucleation proved to be the strongest predictor of HPV DNA-positivity. Binucleation, abnormal mitosis, koilocytosis and spindle koilocytes were also reliable criteria of HPV lesions. Minor nuclear atypia, and "mild koilocytosis" were of no value in making this diagnosis.

Morphological diagnosis of HPV lesions and cervical intraepithelial neoplasia (CIN) is highly reproducible.

PURPOSE: to assess the value of individual histological criteria in the diagnosis of cervical HPV lesions. METHODS: 138 women referred for colposcopic evaluation (due to abnormal PAP smears) were subjected to cervical punch biopsy. The biopsies were classified as no HPV lesion, CIN 1, or CIN 2-3 by two observers independently. Kappa tests were used for interobserver agreement of the diagnosis. The presence of binucleation, multinucleation, abnormal mitosis. koilocytosis, spindle koilocytosis and dyskeratosis was similarly assessed. RESULTS: the Kappa statistic was 0.638 (CI 95% 0.533-0.743), showing substantial inter-observer agreement. Abnormal mitosis and multi-nucleation were the two most powerful discriminators between CIN 2-3 and CIN 1. Koilocytosis proved to be the single most powerful discriminator between CIN 1 lesions and non-HPV lesions. CONCLUSION: the results advocate the use of histology as the gold standard in diagnosing cervical precancerous lesions. The classical criteria can be also used to differentiate low-grade lesions, which has practical implications by avoiding the unnecessary treatment of minor abnormalities.

Systemic and local effects of long-term exposure to alkaline drinking water in rats.

Alkaline conditions in the oral cavity may be caused by a variety of stimuli, including tobacco products, antacids, alkaline drinking water or bicarbonate toothpaste. The effects of alkaline pH on oral mucosa have not been systematically studied. To assess the systemic (organ) and local (oral mucosal) effects of alkalinity, drinking water supplemented with Ca(OH)2 or NaOH, with pH 11.2 or 12 was administered to rats (n = 36) for 52 weeks. Tissues were subjected to histopathological examination; oral mucosal biopsy samples were also subjected to immunohistochemical (IHC) analyses for pankeratin, CK19, CK5, CK4, PCNA, ICAM-1, CD44, CD68, S-100, HSP 60, HSP70, and HSP90. At completion of the study, animals in the study groups had lower body weights (up to 29% less) than controls despite equal food and water intake, suggesting a systemic response to the alkaline treatment. The lowest body weight was found in rats exposed to water with the highest pH value and starting the experiment when young (6 weeks). No histological changes attributable to alkaline exposure occurred in the oral mucosa or other tissues studied. Alkaline exposure did not affect cell proliferation in the oral epithelium, as shown by the equal expression of PCNA in groups. The up-regulation of HSP70 protein expression in the oral mucosa of rats exposed to alkaline water, especially Ca(OH)2 treated rats, may indicate a protective response. Intercellular adhesion molecule-1 (ICAM-1) positivity was lost in 6/12 rats treated with Ca(OH)2 with pH 11.2, and loss of CD44 expression was seen in 3/6 rats in both study groups exposed to alkaline water with pH 12. The results suggest that the oral mucosa in rats is resistant to the effects of highly alkaline drinking water. However, high alkalinity may have some unknown systemic effects leading to growth retardation, the cause of which remains to be determined.