Aspectos histológicos, genéticos y moleculares de las lesiones preneoplásicas de la mucosa gástrica / Histological, genetic and molecular aspects of preneoplastic lesions of the gastric mucosa

Siendo el cáncer gástrico la 3ª causa de muerte por cáncer en Chile, y existiendo estrategias de tamizaje consistentes en pesquisa de lesiones preneoplásicas de la mucosa gástrica, es relevante conocer los aspectos genéticos y moleculares que puedan ser aplicados, en la optimización de dichas estrategias a grupos de mayor riesgo. El objetivo de este manuscrito fue revisar la evidencia actual en los aspectos señalados, y de la inmunohistoquímica de 4 marcadores (p53, CDX2, MUC2 y S100A9) en la mucosa gástrica normal y en las lesiones preneoplásicas de la misma.

SUMMARY: Since gastric cancer is the 3rd leading cause of death from cancer in Chile, and there are screening strategies consisting of screening for preneoplastic lesions of the gastric mucosa, it is important to know certain genetic and molecular aspects that can be applied in optimizing these strategies for higher risk groups. The aim of this manuscript was to review the current evidence on the aforementioned aspects, and on the immunohistochemistry of 4 markers (p53, CDX2, MUC2 and S100A9) in normal gastric mucosa and in its preneoplastic lesions.

Inmunoexpresión de E-cadherina y vimentina en mucosa oral normal, displasia epitelial oral y carcinoma oral de células escamosas / Immunoexpression of E-cadherin and vimentin in normal oral mucosa, oral epithelial displasia and oral squamous cell carcinoma

El objetivo fue evaluar la inmunoexpresión de E-cadherina y Vimentina en mucosa oral normal (MON), displasia epitelial oral (DEO) y carcinoma oral de células escamosas (COCE). Se realizó un estudio descriptivo de una serie de casos analizandolos mediante técnica de inmunohistoquímica contra E-cadherina y Vimentina 16 muestras de MON, 16 de DEO y 19 de COCE. La inmunotinción fue evaluada cualitativamente considerando extensión e intensidad para E-cadherina e intensidad para Vimentina. El análisis de la extensión e intensidad de la inmunotinción de E-cadherina y Vimentina según diagnóstico reveló una asociación estadísticamente significativa (p<0,001). Siendo la expresión de E-cadherina más alta en MON, seguido por DEO y más baja en COCE, inversamente a lo que se observó con Vimentina. El presente estudio reveló la subregulación del marcador molecular E-cadherina junto con la expresión aberrante por parte de células epiteliales del marcador mesenquimal Vimentina en muestras de MON, DEO y COCE.

The aim was to evaluate the expression of E-cadherin and Vimentin in oral epithelial dysplasia (OED) and oral squamous cell carcinoma (OSCC), in comparison with normal oral mucosa (NOM) in a descriptive case study using immunohistochemistry. A total of fifty-one (N=51) histological samples were included; as follows: n = 16 (NOM), n = 16 (OED) and n = 19 (OSCC). All samples were analyzed using immunohistochemistry against the expression of E-cadherin and Vimentin. Immunostaining was qualitatively evaluated by extent and intensity of its expression for E-cadherin and intensity for Vimentin. Extension and intensity analysis of E-cadherin and Vimentin immunostaining according to group revealed a statistically significant association (r<0.001). E-cadherin expression was found to be highest in NOM followed by OED and lowest in OSCC, inverse to what was observed with Vimentin. The present study revealed the down regulation of the molecular marker E-cadherin, suggestive of reduction in dysplastic cells on comparison to NOM cells, and aberrant expression of the mesenchymal marker Vimentin by epithelial cells in samples of NOM, OED and OSCC; questioning their value as a prognostic marker.

Link between immunoexpression of hMLH1 and hMSH2 proteins and clinical-epidemiological aspects of actinic cheilitis

Abstract: Background: The studies found in the literature associate the immunoexpression of hMLH1 and hMSH2 proteins with histologic aspects, but do not correlate it with clinical and epidemiological data. Objective: To evaluate the immunoexpression of hMLH1 and hMSH2 in actinic cheilitis, correlating it with clinical characteristics. Methods: We analyzed 40 cases. Histological and immunohistochemical analyses were performed. The following clinical variables were evaluated: gender, age range, ethnicity, clinical aspect and occupational sunlight exposure. Statistical evaluation included the Student t-test, while the significance level was set at 5%. Results: Greater immunoexpression of hMLH1 and hMSH2 was observed in females, individuals aged over 40, and mixed-race/black patients. Furthermore, the immunoexpression of these proteins was greater in actinic cheilitis with a white-colored appearance and in patients without occupational sunlight exposure. No statistical differences were observed for the variables studied. Conclusion: This study uncovered variations of hMLH1 and hMSH2 protein expression upon evaluation of clinical aspects in actinic cheilitis.

Immunohistochemical expression of MIB-1 and PCNA in precancerous and cancerous lesions of uterine cervix.

BACKGROUND AND OBJECTIVE: The present study was done to analyze the immunoexpression of diagnostic markers (MIB-1: molecular immunology borstel and PCNA: proliferating cell nuclear antigen) in grading cervical intraepithelial lesion (CIN) and squamous cell carcinoma (SCC) in cervix. SETTING AND DESIGN: Total 150 cervical biopsies were divided into four groups respectively; Group I-Normal (n = 32), Group II- CIN (n = 60), Group III- SCC (n = 44), Group IV- CA cervix (n = 14) respectively. MATERIALS AND METHODS: These biopsies were stained with monoclonal antibodies by streptavidin-- biotin method. Mean labeling index was calculated and grading was performed using the I--III scoring system. STATISTICAL ANALYSIS: Findings were correlated with age and menopausal status. Statistical analysis was done by using student sample‘t’ test and analysis of variance (ANOVA) by SPSS 10 package. RESULTS: MIB-1 immunostaining was positive in 112/150 (74.6%) cases and PCNA in 118 /150 (78.6%) cases. Labeling indices showed linear progression from normal to CIN to SCC to cancer lesion. Few cases of low-grade CIN lesion had high proliferative index. A significant positive correlation was found between age and PCNA and MIB-1 values (P < 0.05) when comparison was made for all the cases. CONCLUSION: These markers may be useful in identifying low-grade CIN lesion with high proliferative index. These cases should be kept for follow up studies so that proper intervention can be taken at an early stage. This method is simple and cost effective and can easily be done in formaline-fixed paraffin embedded tissues in a clinical laboratory for grading CIN and SCC lesions in cervix.

Hepatocyte antigen expression in subtypes of intestinal metaplasia of the stomach / Expresión del antígeno del hepatocito en los subtipos de metaplasia intestinal del estómago

OBJECTIVE: Recently, hepatocyte antigen (Hep) was introduced as a sensitive and reliable marker of intestinal metaplasia (IM). However, the distribution of Hep expression in subtypes of IM was not described. METHODS: We examined the expression of Hep in 58 cases of chronic gastritis associated with IM by immunohistochemical staining. Cases were classified as: 19 of IM Type I (complete) cases, 16 cases of IM Type II (incomplete) and 23 cases of IM Type III (incomplete). The distribution of Hep expression was classified into four groups according to the intensity of Hep expressing metaplastic cells: negative, low, moderate and high. We also compared expression of Hep with that of MUC-1, MUC-2 and MUC-5AC. RESULTS: Hep expression showed granular cytoplasmic staining and was specifically identified in columnar cells, but not in goblet cells. There was no significant difference between Hep expression and subtypes of IM (p > 0.005). However, the difference between the distribution of Hep expression among three subtypes of IM was significant (p < 0.001). No relationship was observed among the expression of Hep, MUC-1, MUC-2 and MUC-5AC. CONCLUSION: Results of the present study revealed that the distribution of Hep expression is high in the majority of the complete type (Type I) IM cases, moderate in the majority of the incomplete Type II IM cases and low in all of the incomplete Type III IM cases and suggest that besides its role as a sensitive marker in IM, the evaluation of the distribution of Hep expression might be useful in the classification of IM.

OBJETIVO: El antígeno del hepatocito (Hep) se introdujo recientemente como un marcador sensible y confiable de la metaplasia intestinal (MI). Sin embargo, no se describe la distribución de la expresión de Hep en los subtipos de MI. MÉTODOS: Se examinó la expresión de Hep en 58 casos de gastritis crónica asociados con MI mediante tinción inmunohistoquímica. Los casos fueron clasificados como: 19 casos de tipo MI (completo), 16 casos de tipo MI II (incompleto), y 23 casos de tipo MI III (incompleto). La distribución de la expresión del Hep se clasificó en cuatro grupos según la intensidad de Hep, que expresa las células metaplásticas: negativa, baja, moderada y alta. También se comparó la expresión de Hep con la de MUC-1, MUC-2 y MUC-5AC. RESULTADOS: La expresión de Hep mostró tinción citoplasmática granular, específicamente identificada en las células columnares, pero no en las células caliciformes. No hubo ninguna diferencia significativa entre la expresión de Hep y los subtipos de MI (p > 0.005). Sin embargo, la diferencia entre la distribución de la expresión del Hep entre tres subtipos de MI fue significativa (p < 0.001). No se observó relación alguna entre la expresión de Hep, MUC-1, MUC-2 y MUC-5AC. CONCLUSIÓN: Los resultados del presente estudio revelaron que la distribución de la expresión de Hep es alta en la mayoría de los casos MI de tipo completo (tipo I), moderada en la mayoría de los casos MI de tipo II, y baja en todos los casos MI de tipo III incompleto. Los resultados sugieren que además de su papel como marcador sensible en MI, la evaluación de la distribución de expresión del Hep podría ser útil en la clasificación de MI.

p53 immunoprofiling of potentially malignant oral disorders: A case series analysis.

Context: 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. Aim: The role of p53 was assessed in potentially malignant oral disorders (PMOD) to ascertain its prognostic significance. Settings and Design: Retrospective case series analysis was carried out on 30 paraffin-embedded tissue blocks of confirmed oral leukoplakia with dysplasia. Materials and Methods: 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. Statistics: 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. Results: 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. Conclusions: 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.

Quantitative assessment of expression of cell adhesion molecule (CD44) splice variants: CD44 standard (CD44s) and v5, v6 isoforms in oral leukoplakias: An immunohistochemical study.

Aim: The aim of this study was to semiquantitatively analyze the immunohistochemical expression pattern of CD44 standard (CD44s) and variant (CD44v) isoforms in leukoplakias using a panel of monoclonal antibodies recognizing epitopes of CD44s and of the variant exons v5 and v6. Objective: To evaluate the efficacy of CD44s and CD44 v5, v6 immunoexpression as possible molecular markers in detecting high-risk leukoplakias when screening for this oral precancer. Materials and Methods: Samples of oral leukoplakia (40 cases) and of normal mucosa (10 cases) were evaluated. Oral leukoplakia was graded into: hyperkeratosis without dysplastic change (8 cases), mild dysplasia (13 cases), moderate dysplasia (10 cases), and severe dysplasias (9 cases). Expression of CD44s,v5, v6 was analyzed by immunohistochemistry in a semiquantitative manner. Three areas of epithelium were scored B, S, and C, i.e., stratum basale, stratum corneum, and stratum spinosum, respectively in leukoplakias. Scoring of all specimens followed a two-parameter system, which implemented percentage of positive cells and staining intensities. Statistical analyses for each parameter of all groups and normals, mean, and standard deviation were calculated by using computer software package EPISTAT. Results: In normal epithelium CD44s, CD44v5, and CD44v6 were expressed as membranous proteins localized on the surface of epithelial cells. Both basal and spinous layer of epithelia expressed strong positive staining of CD44s, v5, v6 which then gradually faded into the negative staining of the superficial keratin layer. Profile of CD44s and v5 revealed that the mean levels of stratum B, S, and C in normal cases were comparable to the study cases and by Student 't' test P>0.05 not significant. There was, however, a statistically significant decrease in the expression of v6 with increasing grades of dysplasias when compared with normal mucosa. Conclusion: Among CD44s and its variant isoforms,v5, v6, in this study, variant isoform v6 may serve as a marker in detecting high-risk leukoplakias.

Expression of TERT in precancerous gastric lesions compared to gastric cancer

The objective of this study was to determine the levels of TERT mRNA and TERT protein expression in stomach precancerous lesions such as intestinal metaplasia (IM) and gastric ulcer (GU) and compare them to gastric cancer (GC). Real-time PCR was performed to detect TERT mRNA expression levels in 35 biopsies of IM, 30 of GU, and 22 of GC and their respective normal mucosas. TERT protein was detected by immunohistochemistry in 68 samples, 34 of IM, 23 of GU, and 11 of GC. Increased TERT mRNA expression levels were observed in a significant number of cases, i.e., 46 percent of IM, 50 percent of GU, and 79 percent of GC. The relative mean level of TERT mRNA after normalization with the β-actin reference gene and comparison with the respective adjacent normal mucosa was slightly increased in the IM and GU groups, 2.008 ± 2.605 and 2.730 ± 4.120, respectively, but high TERT mRNA expression was observed in the GC group (17.271 ± 33.852). However, there were no statistically significant differences between the three groups. TERT protein-positive immunostaining was observed in 38 percent of IM, 39 percent of GU, and 55 percent of GC. No association of TERT mRNA and protein expression with Helicobacter pylori infection or other clinicopathological variables was demonstrable, except for the incomplete type vs the complete type of IM. This study confirms previous data of the high expression of both TERT mRNA and protein in gastric cancer and also demonstrates this type of changed expression in IM and GU, thus suggesting that TERT expression may be deregulated in precursor lesions that participate in the early stages of gastric carcinogenesis.

CDX1 and CDX2 Expression in Intestinal Metaplasia, Dysplasia and Gastric Cancer

Intestinal metaplasia (IM) has been regarded as a premalignant condition. However, the pathogenesis of IM is not fully understood. The aim of this study was to evaluate the role of CDX1 and CDX2 in the formation of IM and the progression to dysplasia and gastric cancer (GC). A total of 270 subjects included 90 with GC, dysplasia and age- and sex-matched controls. Real-time PCR (RT-PCR) was performed with body specimens for CDX1 and CDX2. The expression of CDX2 was significantly higher in H. pylori positive group than H. pylori negative group (P = 0.045). CDX1 and CDX2 expression increased proportional to the IM grade of the body (P < 0.001). CDX2 expression was significantly higher in incomplete type of IM than in complete type (P = 0.045). The expression of CDX1 in dysplasia group was significantly higher than in the control group (P = 0.001); in addition, CDX1 and CDX2 in cancer group was significantly higher than control group (P < 0.001, and P < 0.001, respectively). Aberrant expression of CDX1 and CDX2 correlated with H. pylori infection and grade of IM in the body. Furthermore, the results suggest that CDX1 and CDX2 play a role in the progression to GC and dysplasia.

p16INK4 expression in precursor lesions of squamous cell cervical cancer related to the presence of HPV-DNA

The purpose of the present study was to identify the expression of p16INK4 in cervical cancer precursor lesions by immunohistochemistry and to correlate it with lesion grade and presence of human papillomavirus (HPV) infection. Cervical specimens from 144 women seen consecutively at the gynecology outpatient clinic of our institution from December 2003 to May 2005 were analyzed by cytopathology, histopathology, polymerase chain reaction for HPV-DNA, and p16INK4 immunostaining. Histologically normal biopsies, HPV-DNA negative by polymerase chain reaction, were used as control. HPV-DNA prevalence, including the control group, was 68.1 percent and the prevalence of p16INK4 expression was 55.0 percent. The percentage of cells stained by p16INK4 ranged from 10 to 100 percent, both in the group consisting of cervical intraepithelial neoplasia (CIN)1/HPV specimens and in the group of CIN2/CIN3 specimens with P value of 0.0001. p16INK4 expression was 48.3 percent in the CIN1/HPV group, as opposed to 94.3 percent in the CIN2/CIN3 group (P = 0.001), showing a statistically significant difference between the two groups. The quantitative method used here is simple and less subjective than the different semiquantitative methods described in the literature. In view of the different definitions of a p16INK4-positive case, it is almost impossible to compare the findings reported by different investigators. This study confirms the association between p16INK4 and CIN2 and CIN3 lesions. Moreover, it shows that some low grade lesions expressed high levels of this protein. This may indicate that such low grade lesions may be predisposed to progress to high grade lesions. This means that p16INK4 may be a strong marker for "neoplastic lesions" induced by HPV and not just an infection marker.

Intrinsic denervation of the colon is associated with a decrease of some colonic preneoplastic markers in rats treated with a chemical carcinogen

Denervation of the colon is protective against the colon cancer; however, the mechanisms involved are unknown. We tested the hypothesis that the denervated colonic mucosa could be less responsive to the action of the chemical carcinogen dimethylhydrazine (DMH). Three groups of 32 male Wistar rats were treated as follows: group 1 (G1) had the colon denervated with 0.3 mL 1.5 mM benzyldimethyltetradecylammonium (benzalkonium chloride, BAC); G2 received a single ip injection of 125 mg/kg DMH; G3 was treated with BAC + the same dose and route of DMH. A control group (Sham, N = 32) did not receive any treatment. Each group was subdivided into four groups according to the sacrifice time (1, 2, 6, and 12 weeks after DMH). Crypt fission index, ß-catenin accumulated crypts, aberrant crypt foci, and cell proliferation were evaluated and analyzed by ANOVA and the Student t-test. G3 animals presented a small number of aberrant crypt foci and low crypt fission index compared to G2 animals after 2 and 12 weeks, respectively. From the second week on, the index of ß-catenin crypt in G3 animals increased slower than in G2 animals. From the 12th week on, G2 animals presented a significant increase in cell proliferation when compared to the other groups. Colonic denervation plays an anticarcinogenic role from early stages of colon cancer development. This finding can be of importance for the study of the role of the enteric nervous system in the carcinogenic process.

Focos de criptas aberrantes el comienzo de la historia / Aberrant crypts foci, the begining of the tale

Aberrant crypts foci (ACF) are lesions characterized morphologically by abnormal crypts on the surface of the colonic mucosa and since its first description in rats, there has been several lines of evidence that ACF could be a precursor of colorectal cancer. The prevalence of ACF has been estimated in 53,6 per cent in normal people older than 50 years, 90 percent in patients with adenomas an 100 percent in patients with colorectal cancer. ACF are detected most commonly in distal colon and rectum, and these lesions have variable histological findings. There are several genetic abnormalities identified in ACF, and the earliest is the mutation of the gene K-ras. The ACF can be identified in vivo with magnificated endoscopy, methylene blue staining and chromoendoscopy, which allow their use as a marker for colorectal carcinogenesis and even predict the population risks, the individuals that are susceptible to receive chemoprevention and to establish surveillance strategies in colorectal cancer.

Focos de criptas aberrantes (FCA) constituyen lesiones caracterizadas por criptas morfológicamente anormales en la superficie de la mucosa colónica y desde su primera descripción en ratas, ha habido varias líneas de evidencia que sugieren que FCA podrían constituir un precursor de cáncer colorectal (CCR). La prevalencia de FCA ha sido estimada en 53,6 por ciento en sujetos normales mayores de 50 años, 90 por ciento en pacientes con adenoma y 100 por ciento en pacientes con CCR. Los FCA son detectados más comúnmente en colon distal y recto, y desde el punto de vista histológico estas lesiones tienen hallazgos variables. Existen múltiples alteraciones genéticas identificadas en FCA, siendo la más precoz la mutación del gene K-RAS. Los FCA puede ser identificados in vivo con endoscopía con magnificación, tinción de azul de metileno y cromoendoscopía, lo que permite su utilización como marcador para carcinogénesis colorectal y así predecir la población o individuos en riesgo, los que pueden ser susceptibles de recibir quimioprevención y ser incorporados en programas de vigilancia de CCR.

Mucin expression profile in Barrett's, dysplasia, adenocarcinoma sequence in the esophagus.

BACKGROUND: The molecular events that accompany the progression to adenocarcinoma (ADC) of the esophagus are poorly understood. Aberrant mucin receptor expression can contribute to increased cell growth and metastatic ability. AIM: The aim of this study was to establish a pattern for mucin (MUC) gene expression in the esophageal mucosa under normal and pathological conditions. SETTING: University Hospital Cancer Center Laboratory. Archived tissue samples studied in a retrospective fashion. MATERIALS AND METHODS: Tissue samples were obtained from the archives of patients with histological evidence of Barrett's esophagus (BE) progressing to ADC. Immunohistochemical analysis was performed using mouse monoclonal antibodies for MUC1, MUC2, MUC5AC, MUC6. Semiquantitative scoring of histological staining was performed using a linear scoring system: 0-staining absent; 1-staining in 0-25%; 2-staining in 25-50%; and 3-staining in 50-75% of the epithelium. The Binomial test was used to explore trends and differences in frequency of mucin expression along the pathological sequence. RESULTS: Only mild superficial staining of MUC1 was seen in normal squamous epithelium. MUC1 and MUC2 were uniformly expressed in all samples (7/7) of BE and dysplasia (P=0.008). MUC1 expression was upregulated (7/7) in progression to adenocarcinoma (P=0.008). The secretory mucins, MUC5AC and MUC6 showed a decrease in expression with progression from BE to dysplasia to ADC (P< 0.05). CONCLUSIONS: Downregulation of MUC5AC and MUC6 decreases mucosal protection against gastric acid. Increasing MUC1 expression is associated with progression from dysplasia to ADC. Upregulation of MUC2 reflects intestinal metaplasia in BE.

P16(INK4A) expression in Bowen's disease and Bowenoid papulosis.

BACKGROUND: Bowen's disease (BD) is a skin carcinoma in situ occurring over the entire body surface. It shares similar histopathological features with Bowenoid papulosis (BP) of the genitalia, but differs in etiology and clinical course. Increased p16(INK4A) (p16) tumor suppressor protein expression has been demonstrated in relation to the progression of cutaneous squamous neoplasms. OBJECTIVE: To evaluate the difference in p16 expression between Bowen's disease and Bowenoid papulosis. MATERIAL AND METHOD: Biopsies of 46 cases of BD in the period 1994 - 2003 and 14 cases of BP during 1987 - 2003 in the Anatomical Pathology Unit, Department of Pathology, Faculty of Medicine, Prince of Songkla University, Thailand were studied by immunohistochemical methods using the P16 kit (CINTec Histology Kit, clone E6H4, Code-Nr. K5334, DakoCytomation, Denmark). Nuclear/cytoplasmic immunoreactivity in more than 10% of neoplastic cells was considered positive. RESULTS: P16 expression was positive in 37 of 46 BD cases (80.4%) which was higher than that of BP (6 of 14 cases or 42.9%) (p value < 0.05, Chi-square test). The expression among the three groups of BD: extragenital (28 of 35), chronic arsenical-related (7 of 8) and genital lesions (2 of 3) was not significantly different (p value = 0.734, Chi-square test). CONCLUSION: P16 expression was more frequent in BD than BP. This suggests a possible association between p16 expression and tumorigenesis of these lesions.

Histological and histochemical changes of the intestinal mucosa at the urothelial-enteric anastomotic site

OBJECTIVE: The incorporation of bowel segments for urinary tract reconstruction may induce intestinal mucosal changes with the development of metabolic, nutritional, gastrointestinal and carcinogenic complications. The early histological and histochemical changes of the intestinal mucosa in contact with the feces-urine mixture, are evaluated in the present study. MATERIALS AND METHODS: Twelve rats (operated group) were submitted to a vesico-colonic anastomosis, and 10 rats (control group) underwent a sham operation (the colon was opened and immediately sutured). On the operated group, the left colon was divided into 3 equal portions and the middle segment was used for the bladder-colonic anastomosis. After 20 weeks, the animals were sacrificed and the entire left colon in each group, as well as the bladder and the vesico-colonic anastomosis in the operated group, was removed. The proximal, middle (anastomotic site in the operated group and sutured portion in the control group) and distal colon were used for histological and histochemical studies. RESULTS: Metaplasia, chronic inflammatory process and fibrosis were significantly greater at the anastomotic site compared to the middle segment of the control group. There were no differences in both groups in terms of dysplasia, atrophy and hypertrophy either on the proximal, middle or anastomotic area and distal portion of the left colon. All animals in the operated group showed a reduced presence of sulfomucin and an increase in the sialomucin content. CONCLUSION: The histological changes observed in this study may suggest a precancerous phenomenon.

Expression of lectin binding in oral submucous fibrosis.

Lectins are a group of specific glycoproteins present in cells, particularly cell membrane. Recently, lectin binding studies have been used as a diagnostic as well as prognostic indicator of neoplasm's. Oral submucous fibrosis (OSMF) is a potential premalignant condition predominantly seen in Indian subcontinent. A comparison of expression of lectin binding was studied in normal tissue, OSMF cases and oral squamous cell carcinoma. The OSMF cases were grouped into early and advanced conditions as per the histopathologic criteria. Patterns of lectin binding observed with advanced OSMF cases were comparable with that of Oral squamous cell carcinoma. The role of lectin binding studies in assessing the malignant potential of a pre-malignant condition is discussed.