Squamous Cell Hyperplasia Research Articles

Vulvar intraepithelial neoplasia and vulvar squamous cell carcinoma: a clinicopathologic study of 18 cases

Background: The vulvar intraepithelial neoplasia is divided into two groups: usual type and differentiated type. The differentiated vulvar intraepithelial neoplasia which is frequently seen together with the invasive squamous cell carcinoma can be confused with some benign lesions. To analyse p16, p53, and Ki-67 expression characteristics of different histological types of invasive squamous cell carcinoma of the vulva and vulvar intraepithelial neoplasia is aimed in this study. Methods: In this study, immunohistochemical analysis of 18 vulvectomy cases with p16, p53, and Ki-67 was performed. Results: Of 18 patient who underwent vulvectomy, 9 had invasive squamous cell carcinoma and 9 vulvar intraepithelial neoplasia. 3 additional vulvar intraepithelial neoplasia lesions were found accompanying the invasive squamous cell carcinomas. Mean Ki-67 PI was 32,3% in usual type (human papilloma virus-related) vulvar intraepithelial neoplasia cases (n:9), and 26,4% in differentiated vulvar intraepithelial neoplasia cases (n:3)(p>0,05). Mean p16 staining degree was 2,6 for usual type vulvar intraepithelial neoplasias. No p53 expression was present in squamous cell hyperplasia or lichen sclerosis lesions. Conclusions: Ki-67 PI does not have significant value in recognizing vulvar intraepithelial neoplasia usual type and differentiated vulvar intraepithelial neoplasia. p53 positivity can be of value in distinguishing especially differentiated type vulvar intraepithelial neoplasia from benign lesions.

Expressions of epidermal growth factor receptor (EGFR) and Ki-67 in vulvar dystrophy

Objective To explore the expressions of EGFR and Ki-67 in vulvar dystrophy and their clinical significance Methods Tissue specimens were collected from 160 patients with vulvar dystrophy.Immunohistochemical method was used to detect the expressions of EGFR and Ki-67 in these specimens.The expression levels of EGFR and Ki-67 were compared among different pathological subtypes of vulvar dystrophy,and the relationship of these expressions with clinical pathological characteristics was assessed.Results No significant differences were observed in the expressions of EGFR or Ki-67 between vulvar dystrophy of squamous cell hyperplasia type,lichen sclerosus type and mixed type (P ＞ 0.05).The expression level of EGFR was positively correlated with that of Ki-67 in vulvar dystrophy (r =0.66,P ＜ 0.05).There was a significant difference in the expression rate of EGFR and Ki-67 between patients with different courses of vulvar dystrophy (both P ＜0.05),but not between patients with different age at onset of vulvar dystrophy (both P ＞ 0.05).Conclusion The expressions of EGFR and Ki-67 are different among patients with different courses of vulvar dystrophy.

Medium-term multi-organ carcinogenesis bioassay of ethyl tertiary-butyl ether in rats

The modifying potential of ethyl tertiary-butyl ether (ETBE) on tumor development was investigated in a medium-term multi-organ carcinogenesis bioassay using male F344 rats. Animals were sequentially given 5 carcinogens with different target sites in the first 4 weeks for multi-organ initiation. After one week they received ETBE by gavage at dose levels of 0 (control), 300 or 1000 mg/kg/day until experimental week 28. Further groups were also given ETBE at doses of 0 or 1000 mg/kg/day without prior carcinogen application. Incidences and multiplicities of follicular cell hyperplasias and neoplasms in the thyroid were significantly increased at dose levels of more than 300 mg/kg/day. Combined incidences of squamous cell hyperplasias and papillomas of the forestomach were also significantly increased at 300 and 1000 mg/kg/day. Incidences and multiplicities of adenocarcinomas in the colon were increased at 1000 mg/kg/day. The numbers and areas of glutathione S-transferase placental form (GST-P) positive foci per unit area of the liver sections, and the incidence of hepatocellular adenomas were also significantly increased at 1000 mg/kg/day, along with multiplicities of atypical hyperplasias of renal tubules of the kidney and the incidence of papillomatosis of the urinary bladder. This latter lesion was also seen at low incidence at 1000 mg/kg/day without initiation. Thus, the current results indicate that ETBE has tumor promoting potential for the thyroid and forestomach at dose levels of 300 mg/kg/day and more, and for the colon, liver, kidney and urinary bladder at 1000 mg/kg/day, under the present experimental conditions.

Overexpression of Prothymosin Alpha Predicts Poor Disease Outcome in Head and Neck Cancer

BackgroundIn our recent study, tissue proteomic analysis of oral pre-malignant lesions (OPLs) and normal oral mucosa led to the identification of a panel of biomarkers, including prothymosin alpha (PTMA), to distinguish OPLs from histologically normal oral tissues. This study aimed to determine the clinical significance of PTMA overexpression in oral squamous cell hyperplasia, dysplasia and head and neck squamous cell carcinoma (HNSCC).MethodologyImmunohistochemistry of PTMA protein was performed in HNSCCs (n = 100), squamous cell hyperplasia (n = 116), dysplasia (n = 50) and histologically normal oral tissues (n = 100). Statistical analysis was carried out to determine the association of PTMA overexpression with clinicopathological parameters and disease prognosis over 7 years for HNSCC patients.ResultsOur immunohistochemical analysis demonstrated significant overexpression of nuclear PTMA in squamous cell hyperplasia (63.8%), dysplasia (50%) and HNSCC (61%) in comparison with oral normal mucosa (ptrend<0.001). Chi-square analysis showed significant association of nuclear PTMA with advanced tumor stages (III+IV). Kaplan Meier survival analysis indicated reduced disease free survival (DFS) in HNSCC patients (p<0.001; median survival 11 months). Notably, Cox-multivariate analysis revealed nuclear PTMA as an independent predictor of poor prognosis of HNSCC patients (p<0.001, Hazard's ratio, HR = 5.2, 95% CI = 2.3–11.8) in comparison with the histological grade, T-stage, nodal status and tumor stage.ConclusionsNuclear PTMA may serve as prognostic marker in HNSCC to determine the subset of patients that are likely to show recurrence of the disease.

Evaluation of double vital staining with lugol's iodine and methylene blue in diagnosing superficial esophageal lesions

Objective. To evaluate the accuracy of double vital staining with lugol's iodine and methylene blue in the diagnosis of superficial esophageal lesions. Methods. Doubtful superficial esophageal lesions identified with conventional endoscope were sprayed with 3% lugol's iodine and 0.5% methylene blue in order and observed in detail after each staining. Depending on the mucosal staining, biopsy specimen was obtained and underwent pathological examination. Results. Using conventional endoscope, we found 356 lesions in 297 patients, among which 179 were esophageal squamous cell carcinoma and precancerous lesions (CAPs) (including 71 early esophageal squamous cell carcinoma, 23 esophageal high-grade intraepithelial neoplasias, 85 esophageal low-grade intraepithelial neoplasias) and 177 were non-cancer non-precancerous lesions (NCNPs) (i.e. esophagitis and esophageal squamous cell hyperplasia). Most of CAPs were lightly stained or unstained, while NCNPs were hyperstained after lugol's iodine stained. The specificity, sensitivity, positive predictive value, negative predictive value and accuracy of lugol's lightly stained and unstained for identifying CAPs were 34.5%, 100%, 60.7%, 100% and 67.4%, respectively. Most of CAPs were lightly stained or hyperstained, while NCNPs were unstained after double vital staining. The specificity, sensitivity, positive predictive value, negative predictive value and accuracy of double vital staining lightly stained and hyperstained for identifying CAPs were 97.7%, 100%, 97.8%, 100% and 98.9%, respectively. The accuracy of double vital staining for identifying CAPs was higher than that of lugol's iodine stained (p = 0.000). Conclusion. The double staining with lugol's iodine and methylene blue significantly improves the detection and diagnosis of early esophageal squamous cell CAPs.

Lack of skin carcinogenicity of topically applied titanium dioxide nanoparticles in the mouse

This study was conducted to examine the post-initiation carcinogenic potential of coated and uncoated titanium dioxide nanoparticles (CTDN and UCTDN) using a mouse medium-term skin carcinogenesis bioassay. For this purpose, 5, 10 and 20 mg/animal doses of CTDN or UCTDN were applied to mouse skin in the post-initiation phase (up to 20 weeks) in a two-stage skin carcinogenesis model using 7 week old CD1 (ICR) female mice. 7,12-dimethylbenz[ a]anthracene (DMBA) and 12- o-tetradecanoylphorbol 13-acetate (TPA) were used as the initiator and a positive control promoter, respectively. Pentalan 408 served as a vehicle control. No changes in survival rate, general condition and body weight related to the test materials were observed. On macroscopic observation, 1–2 nodules/group on the skin were observed in each group applied CTDN and UCTDN as well as the control group after DMBA initiation. The nodules were histopathologically diagnosed as squamous cell hyperplasia, sebaceous gland hyperplasia, squamous cell papilloma and keratoacanthoma. CTDN and UCTDN experiments, while enlargement of the mandibular, pancreatic, lumbar region and inguinofemoral lymph nodes, spleen and thymus was observed in mice given 5 and 10 mg but not 20 mg, the lack of dose-dependence suggests no biological significance. In the present study, CTDN and UCTDN applied in post-initiation stages at doses of up to 20 mg/mouse did not increase the development of nodules, and thus it was concluded that titanium dioxide nanoparticles do not possess post-initiation potential for mouse skin carcinogenesis.

Inhalation carcinogenicity and toxicity of 1,2-dichloropropane in rats

The toxicity and carcinogenicity of 1,2-dichloropropane (DCP) were examined by inhalation exposure of male and female F344 rats to DCP for either 13 wk or 2 years. In the 13-wk study, the DCP concentrations used were 125, 250, 500, 1000, or 2000 ppm (v/v), and in the 2-year study the DCP concentrations were 80, 200, or 500 ppm (v/v). Thirteen-week exposure to DCP induced hyperplasia in the respiratory epithelium and atrophy of the olfactory epithelium at 125 ppm and above. At the higher levels of exposure, hemolytic anemia and lesions of liver and adrenal gland were observed. Two-year exposure to DCP significantly increased incidences of papilloma in the nasal cavity of male and female rats exposed to 500 ppm DCP. In addition, three cases of esthesioneuroepithelioma were observed in the DCP-exposed male rats. Total nasal tumors increased in a concentration-dependent manner. Hyperplasia of the transitional epithelium and squamous cell hyperplasia, both of which were morphologically different from the hyperplasia of the respiratory epithelium observed in the 13-wk exposure study, occurred in a concentration-dependent manner; these lesions are considered to be preneoplastic lesions. Atrophy of the olfactory epithelium, inflammation of the respiratory epithelium, and squamous cell metaplasia were also seen in the 2-year study. These results demonstrate that DCP is a nasal carcinogen in rats. Lifetime cancer risks for humans exposed to DCP in the ambient air and work environment were quantitatively estimated, using both nonthreshold and threshold approaches, with the data obtained from the 2-year study.

Inter-observer Agreement in Laryngeal Pre-neoplastic Lesions

In this series, laryngeal preneoplastic lesions were evaluated by the classifications of the World Health Organization (WHOC), Ljubljana (LC) and squamous intraepithelial neoplasia (SINC) by multiple observers. The inter-observer agreement (IA) by WHOC for laryngeal lesions had been previously evaluated, but to the best of our knowledge, there are no data for LC and SINC. H&E stained slides from 42 laryngeal biopsies were evaluated by fourteen participants according to WHOC and LC, and SINC was additionally applied by 6. The results were analyzed statistically. The diagnoses which were favored by most participants for each case, according to WHOC, were as follows: squamous cell hyperplasia (n=5; 12%), mild dysplasia (n=11; 26.2%), moderate dysplasia (n=12; 28.6%), severe dysplasia (n=7; 16.7%), carcinoma in situ (n=5; 12%), and invasive squamous cell carcinoma (n=2; 4.8%). There was a significant difference between the participants for all three classifications; some participants gave lower or higher scores than the others. The mean correlation coefficients (MCC) of the participants were higher for WHOC compared to LC (0.55±0.15 and 0.48±0.14, respectively). The mean linear-weighted kappa (wKappa) values of participants were not significantly different (0.42±0.10, 0.41±0.12 and 0.37±0.07 for WHOC, LC and SINC, respectively). The kappa values in this series are in agreement with those in previous literature for WHOC, and the similar results obtained for LC and SINC are novel findings. Although the MCC of WHOC was higher, as the wkappa was not significantly different, the findings in this series are not in favor of any of the classifications for better IA for pre-neoplastic laryngeal lesions.

A 90-day oral toxicity study of nisin A, an anti-microbial peptide derived from Lactococcus lactis subsp. lactis, in F344 rats

This study was designed to evaluate and characterize any adverse effect of nisin A, when administered to both sexes of F344/DuCrlCrlj rats (10 males and 10 females in each group) at dietary levels of 0%, 0.2%, 1.0% and 5.0% for 90 days. Animals given NaCl at a dietary level of 3.712% (equivalent to the NaCl content in 5.0% nisin A diet) served as a reference material treated group. There were no deaths, and the treatment had no toxicologically significant effects on clinical signs, body weights, food consumption, ophthalmology, hematology, or gross pathology. Statistically significant increases of water consumption, urine volume, and urinary sodium and chlorine, and decreases of urinary potassium and serum sodium, along with increases of absolute and relative kidney weight, and incidences of minimal squamous cell hyperplasia of limiting ridge in the forestomach, were found in nisin A-treated groups. It was considered that these changes were related to NaCl, since they were also noted in rats given diet containing the reference substance. Thus, no toxicologically significant changes were apparent in both sexes of F344/DuCrlCrlj rats fed diet containing 0%, 0.2%, 1.0% and 5.0% nisin A for 90 days. Therefore, the no-observed-adverse-effect level (NOAEL) for nisin A was concluded to be a dietary level of 5.0% (2996 mg/kg/day for males and 3187 mg/kg/day for females).

High-intensity focused ultrasound treatment for non-neoplastic epithelial disorders of the vulva

Objective To assess the efficacy of high-intensity focused ultrasound (HIFU) treatment in patients with non-neoplastic epithelial disorders of the vulva. Method We reviewed 41 cases of lichen sclerosus, 38 cases of squamous cell hyperplasia, and 17 mixed cases treated by HIFU from April 2004 to July 2008 at the Women's Hospital of Zhejiang University School of Medicine. Biopsy specimens were assessed with light microscopy before and after treatment. Results Pruritus and signs of vulvar lesions were dramatically improved following HIFU treatment, without severe complications, and 90.23% of the patients were cured or had their symptoms improved 6 months after treatment. On light microscopy, pigmentation and epithelial structures were recovered and dermal lymphocytic infiltration was reduced. The response rates were lower and complication rates higher among lichen sclerosus than among squamous cell hyperplasia cases ( P < 0.05 for both). Conclusion Treatment with HIFU may be safe and effective in cases of vulvar dystrophy.

HPV-negative Vulvar Intraepithelial Neoplasia (VIN) With Basaloid Histologic Pattern

Vulvar intraepithelial neoplasia (VIN) is classified into 2 clinicopathologic subtypes, classic, related to human papillomavirus (HPV) infection and affecting relatively young women, and simplex (differentiated), negative for HPV and affecting elderly women. Histologically, classic VIN may be basaloid and characterized by a replacement of the whole epidermis by a homogeneous population of small, "undifferentiated" keratinocytes, which are diffusely positive for p16(INK4a) and negative for p53. Simplex VIN is characterized by atypia of the basal layer with high degree of cellular differentiation and shows negative staining for p16(INK4a) and frequent positivity for p53. Simplex VIN is frequently associated with squamous cell hyperplasia and lichen sclerosus. From a series of 110 invasive squamous cell carcinomas of the vulva negative for HPV by highly sensitive polymerase chain reaction, 51 had VIN lesions located at least 1 cm away from the tumor. In 4 (7.8%) cases, the VIN had basaloid histologic features. All cases showed obvious architectural disorganization with a homogeneous population of basaloid, undifferentiated keratinocytes with scanty cytoplasm replacing the whole epidermis. Immunohistochemically, all cases were negative for p16(INK4a) and strongly positive for p53 with suprabasilar extension of positive cells. All patients were postmenopausal (median age 61.0 y; range, 45-76). Squamous cell hyperplasia was identified in 1 case and lichen sclerosus in 1 case. The invasive squamous cell carcinoma was of keratinizing type in 3 cases and basaloid in 1 case. In conclusion, simplex, HPV-negative VIN may occasionally have basaloid morphology. Immunostaining for p16(INK4a) and p53 protein may be helpful in the identification of these lesions and the differential diagnosis with classic, HPV-positive basaloid VIN.

Paradoxical effects of a selective cyclooxygenase-2 inhibitor, etodolac, on proliferative changes of forestomach in alloxan-induced diabetic rats

A single intravenous injection of alloxan, a non-genotoxic diabetogenic chemical, induces proliferative changes in forestomach mucosa of rats, and some lesions progress to squamous cell carcinoma accompanied with inflammatory change. The present study was conducted to examine the effects of a selective cyclooxygenase-2 (COX-2) inhibitor, etodolac, on the proliferative changes of forestomach mucosa in alloxan-induced diabetic rats. Alloxan-induced diabetic rats were fed a diet containing 0.01% etodolac (AL+Et group) and standard diet (AL group). They were sacrificed after 25 and 50 weeks of feeding, respectively. Squamous cell hyperplasia of forestomach was completely suppressed by etodolac after 25 weeks. After 50 weeks of treatment, the proliferative changes in forestomach developed in all rats of the AL+Et group, but in only 55.6% of the rats in the AL group. The severity of proliferative lesions was much enhanced in the AL+Et group compared to the AL group, and was parallel to the inflammatory changes in individual cases. Ulceration and erosion were more severe in the AL+Et group. These findings demonstrate that etodolac suppresses proliferative and inflammatory changes with COX-2 expression of forestomach in the early stage, but enhances them after 50 weeks.

Combined repeated dose and reproductive/developmental toxicities of copper monochloride in rats

This study investigated the combined repeated dose and reproductive/developmental toxicity of copper monochloride in rats. The test substance was administered once daily by gavage at 0, 1.3, 5, 20, or 80 mg/kg/day. Male rats were dosed for a total of 30 days beginning 14 days before mating. Female rats were dosed from 2 weeks before mating to day 3 of lactation throughout the mating and gestation period. At 80 mg/kg/day, deaths were observed in 3 out of 12 females. There was a dose-dependent increase in the incidence of clinical signs and a reduction in the food consumption. Hematological and serum biochemical investigations revealed a decrease in the red blood cell, hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin (MCH), and serum total protein levels and an increase in the white blood cell and platelets in males, and a decrease in the MCH and an increase in the platelets in females. Histopathological examination showed an increased incidence of squamous cell hyperplasia of the stomach in both genders as well as increased hematopoiesis of the femur in males. There was an increase in the number of icteric and runt pups at birth. At 20 mg/kg/day, there was an increase in the incidence of clinical signs and squamous cell hyperplasia of the stomach in both genders. At 5 mg/kg/day, an increase in the incidence of squamous cell hyperplasia of the stomach was observed in females. There were no adverse effects in the lowest group in both genders. Based on these findings, the no-observed-adverse-effect levels of copper monochloride were concluded to be 5 mg/kg/day in male rats and 1.3 mg/kg/day in female rats for general toxicity and 20 mg/kg/day for reproductive/developmental toxicity.

A Morphologic and Immunohistochemical Study of Nasal Mucosa in Leatherworkers

The association between intestinal-type sinonasal adenocarcinoma and the occupational exposure to leather dusts has been widely documented, but the identification of precursor lesions in exposed workers has remained controversial. The purpose of this study was to investigate the histological changes and modifications in the phenotype of epithelial cells in nasal mucosa of leather workers. Biopsy specimens of the mucosa of the middle turbinate were obtained from 139 subjects who had been employed in leather factories for 10-48 years (median, 29 years). Tissue fragments were routinely processed for histological examination and immunostainings for cytokeratin 20, CDX-2, and MUC-2 were performed. Regarding the surface epithelium, the most common histopathological finding was the presence of squamous metaplasia (64.7%), which was associated with mild to moderate dysplasia in 37 cases (41.1%), and goblet cell hyperplasia was identified in 30 biopsy specimens (21.6%). Positivity for MUC-2 was detected in goblet cells of 20 of the 30 samples with goblet cell hyperplasia (66.6%), whereas no immunostaining was observed for cytokeratin 20 and CDX-2. Presence of goblet cell hyperplasia was significantly associated with longer occupational exposure in leather tanning activities (p = 0.03). None of the alterations observed (squamous metaplasia, dysplasia, or goblet cell hyperplasia) showed correlation with smoking habits. Similarly, there was no correlation between squamous metaplasia with or without dysplasia and type and duration of occupational exposure. Our data identify goblet cell hyperplasia as possible work-related alterations of nasal mucosa in leather workers. Additional investigations are needed to clarify the significance of these findings in the development of sinonasal intestinal-type carcinoma.

Testosterone Versus Clobetasol for Maintenance of Vulvar Lichen Sclerosus Associated With Variable Degrees of Squamous Cell Hyperplasia

What used to be called vulvar dystrophy now is termed nonneoplastic epithelial disorders of the vulva. Within this category, the association of lichen sclerosus with varying degrees of squamous cell hyperplasia is referred to as mixed disease. This retrospective study compared responses to treatment with testosterone and clobetasol in 83 women having biopsy-proved vulvar mixed disease. All patients were initially treated with topical fluorinated corticosteroids for 6 weeks. They were then treated with either 2% testosterone propionate in petrolatum (n = 44) or 0.05% clobetasol 17-propionate cream (n = 39), each applied once a day. After symptoms were optimally controlled, twice weekly applications were advised for 3 months and treatment then was continued on an as-needed basis. The major complaints were vulvar itching and burning or discomfort. Remission rates after 6 months were 82% in women treated with testosterone and 93% in those treated with clobetasol. Disease recurred in 8% of patients: 13% of women treated with testosterone and 5% of clobetasol-treated patients. The median time to recurrence was 9 months. Persistent disease was documented histologically in 60% of patients whose symptoms did not respond to treatment. Skinning vulvectomy ultimately was performed in 2 patients with recurrent disease and 2 with vulvar intraepithelial neoplasia I–II or atypical squamous hyperplasia. Treatment was not associated with steroid vulvar atrophy or other serious complications. Both topical treatments evaluated in this retrospective study yielded excellent remission rates. Clobetasol led to a higher remission rate and lower recurrence rate than did testosterone therapy, but the differences were not statistically significant. Patients with mixed disease who fail to respond symptomatically should have a vulvar biopsy to rule out atypical components.

Testosterone versus clobetasol for maintenance of vulvar lichen sclerosus associated with variable degrees of squamous cell hyperplasia

To evaluate the therapeutic regimens and symptomatic response rates in patients with vulvar lichen sclerosus associated with variable degrees of squamous cell hyperplasia (mixed disease). Eighty-three women with biopsy-proven vulvar mixed disease were evaluated for this retrospective study. All patients were initially treated with topical fluorinated corticosteroids, and then 2% testosterone propionate in petrolatum or 0.05% clobetasol 17-propionate (44 (53%) versus 39 (47%)). The remission rates were 82 and 93% in the testosterone and clobetasol subgroups at the end of 6 months (p=0.112), respectively. The disease recurred in 8% of the patients. The recurrence rates in the testosterone and clobetasol arms were 13 and 5%, respectively (p=0.163). The histopathological review of the repeat vulvar biopsies of the patients without symptomatic relief revealed 6 (60%) patients with persistent disease, 2 (20%) with lichen sclerosus, 1 (10%) with atypical squamous hyperplasia, and 1 (10%) with VIN1. Two patients with recurrent disease and 2 patients with vulvar intraepithelial neoplasia I-II or atypical squamous hyperplasia were treated with skinning vulvectomy. Clobetasol resulted in higher remission and lower recurrence rates than those in testosterone therapy, although statistically significant differences were not obtained. In the evaluation of patients without symptomatic relief, the first step should be a vulvar biopsy to exclude the presence of atypical components.

Organ‐dependent susceptibility of p53 knockout mice to 2‐amino‐3‐methylimidazo[4,5‐f]quinoline (IQ)

p53 knockout mice are now being frequently used to identify the carcinogenic potential of chemicals, thus it is important to precisely assess the susceptibility of the animals to various test chemicals. In the present study the susceptibility of p53 nullizygous((-/-)), heterozygous((+/-)), and wild-type((+/+)) mice to 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) was investigated. Mice of all three genotypes were first fed a diet containing 100 or 300 p.p.m. IQ for 15 weeks in a short-term experiment. p53((+/-)) and ((+/+)) mice were then treated with IQ for 40 weeks and maintained without further treatment for an additional 12 weeks in the long-term experiment. In the forestomach, the incidence of squamous cell hyperplasia was significantly higher in p53((-/-)) than in ((+/-)) and ((+/+)) mice at 15 weeks and higher in ((+/-)) mice than ((+/+)) mice with long-term IQ treatment, indicating an elevated susceptibility of p53 knockout mice. In contrast, in the liver, various hepatocellular lesions developed mainly in female mice with long-term IQ exposure but no significant differences were evident between p53 knockout and wild-type mice, indicating a lack of elevated susceptibility in the knockout animals. Furthermore, polymerase chain reaction-single strand conformation polymorphism and sequencing analysis revealed relatively high (13/30) and low (1/15) incidences of p53 mutations (exons 5-8) in squamous cell hyperplasia and hepatocellular tumors, respectively. These results clearly indicate that the susceptibility of p53 knockout mice is organ-dependent, coinciding to some extent with the likelihood of p53 gene alteration in the induced tumors.

EXAMINATION OF PERCUTANEOUS APPLICATION IN A 26-WEEK CARCINOGENICITY TEST IN CB6F1-TG rasH2 MICE

We examined the possibility of expanding applications of rasH2 mice, which are genetically manipulated mice for short-term carcinogenicity tests, to percutaneous application. A 26-week short-term carcinogenicity study was performed on a total of 300 mice including 75 male and female rasH2 mice each, and 75 male and female non-Tg mice each from the same litter as the rasH2 mice divided into untreated group, an ethanol group, a white Vaseline group, an acetone group, and a phorbol 12-myristate 13-acetate (TPA) group. Only shaving of dorsal skin was performed on the untreated mice. As a positive control, TPA was administered percutaneously at a dose of 2.5 microg/kg and 3 times/week for 26 weeks based on the protocol for Tg.AC mice in the ILSI/HESI international validation study. In the ethanol, white Vaseline, and acetone groups, no tumorous changes were observed on the skin at the administration site. In the TPA group, nodular changes at the administration site were observed from seven weeks after the start of administration in rasH2 mice, and the incidence in males and females was 50.0% (7/14) and 53.3% (8/15), respectively. In a pathological examination, nodules in 21.4% (3/14) of males and 46.7% (7/15) of females were diagnosed as skin papilloma or keratoacanthoma, and the rest as squamous cell hyperplasia. In the non-Tg mice, no nodules or tumorigenic changes were observed at the administration site. These findings show that percutaneous application in rasH2 mice is possible in 26-week carcinogenicity tests.

Medical treatment of vulvar squamous cell hyperplasia

Objective To evaluate symptomatic response and recurrence rates of graduated topical fluorinated corticosteroid in patients with vulvar squamous cell hyperplasia. Methods Nine hundred seventy-six patients with biopsy-proven vulvar squamous cell hyperplasia from 1990 to 2003 were reviewed in this retrospective study. All patients were treated with graduated topical fluorinated corticosteroid. Data were obtained from hospital records. Symptomatic remission and recurrence rates were noted following six months local therapy. Results The mean age was 42.55 ± 10.93 (15-85). The remission rate was 93.8% in six months. The remission rate was non-significantly higher in postmenopausal patients than that in their premenopausal counterpart (94.9% vs 93.0%, p = 0.15). The disease recurred in 6.9% of patients. Of the patients that suffered recurrence 47.5% had persistent disease initially. The patients with following factors older ages (>40 years), postmenopausal period had significantly higher recurrence rates. Four patients with recurrent disease and six patients with persistent disease in the form of vulvar intraepithelial neoplasia I-II or atypical squamous hyperplasia, were treated with skinning vulvectomy. Conclusion Corticosteroid in the treatment of vulvar squamous cell hyperplasia yielded excellent response rates. In the evaluation of patients without symptomatic relief, the first step should be a vulvar biopsy to exclude the presence of atypical components.

Histopathologic Evaluation of an Animal Model for Barrett’s Esophagus and Adenocarcinoma of the Distal Esophagus

Barrett's esophagus and adenocarcinoma of the esophagus are related to long-standing duodeno-gastroesophageal reflux. The development of an animal model in which Barrett's esophagus and/or carcinoma is induced by duodeno-(gastro-)esophageal reflux could provide better understanding of the pathogenesis of the metaplasia-dysplasia-carcinoma sequence and would create the possibility of investigating new treatment strategies for this aggressive disease. Two rat models were analyzed. In the first experiment, 44 male Sprague Dawley rats underwent end-to-side esophagojejunostomy with gastric resection, to ensure duodenoesophageal reflux without gastric acid. In the second experiment a side-to-side esophago-gastrojejunostomy was performed in 30 rats, ensuring duodeno-gastroesophageal reflux. In both experiments animals were not exposed to any exogenous carcinogens during the experiment. Sequential morphological changes (i.e., esophagitis, intestinal metaplasia, dysplasia, and carcinoma) were studied after 4, 6, and 12 months. To analyze histopathologic characteristics, evaluation of the hematoxylin and eosin specimens was combined with immunohistochemical stainings for high-iron diamine-alcian blue, alcian blue/periodic acid-Schiff, the proliferation marker PCNA, and mutations in the tumor suppressor gene p53. In the first experiment, only 11 animals survived the postoperative period. These animals had to be sacrificed at a median of 11 weeks due to persistent weight loss and failure to thrive. Severe ulcerative esophagitis was seen in all animals, with a 2-mm segment of metaplastic epithelium found at the anastomosis. In four animals a large, well-differentiated, mucinous tumor without malignant characteristics was observed. In the second experiment, eight animals died postoperatively. Twelve animals were sacrificed according to protocol at 4 or 6 months. In these animals, extensive esophagitis with squamous cell hyperplasia was found. In addition, a short (2 mm) segment of metaplastic epithelium was observed, without dysplasia. The remaining animals survived 1 year. After 1 year, 9 of the 10 animals had developed a glandular metaplastic segment (median length, 10 mm), which was histologically and immunohistologically characteristic for the specialized columnar epithelium of Barrett's esophagus without signs of dysplasia. Finally, in seven animals a mucinous tumor with cytologic characteristics of a well-differentiated mucinous adenocarcinoma was found without infiltrative growth. These tumors were always found at the site of the anastomosis, originated in the submucosa, and did not reach either the luminal surface or the muscular layer. The mucinous lesions were not positive for p53, and PCNA was only slightly increased. Although they showed cytological characteristics of malignancy, histopathologic evaluation was more suggestive of a reactive mucous producing lesion fitting the diagnosis "esophagitis cystica profunda." This study demonstrates the development of a long Barrett's segment in an animal duodeno-gastroesophageal reflux model. Although mucinous tumors resembling adenocarcinomas develop around the anastomosis, these are probably not reflux induced and are more likely to be reactive lesions. However, the true nature of these tumors remains to be elucidated.