Esophagin and proliferating cell nuclear antigen (PCNA) are biomarkers of human esophageal neoplastic progression

PCNA and esophagin have been implicated in the multistep process of carcinogenesis, but simultaneous characterization of these proteins in the early stages of esophageal neoplastic progression has yet to be undertaken. In morphologically normal esophageal epithelium, esophagin stains the granular layer cells, principally in their cell membrane portions. PCNA, in contrast, stains the nuclei of cells in the parabasal and basal layers. We examined 201 regions from 47 patients that represented different stages of esophageal neoplasia, comprising 34 areas of normal mucosa, 18 of dysplasia in squamous epithelium (DYS/SC), 39 squamous cell carcinoma (SCCA), 29 areas of Barrett's esophagus, 48 of Barrett's dysplasia (DYS/BAR) and 33 areas of adenocarcinoma (AC). The immunostaining patterns of esophagin and PCNA were evaluated and graded for level of expression. There was loss of esophagin expression in the high- and low-grade dysplasias compared to normal epithelia. In the squamous dysplasias, there was more intense staining (of esophagin) in the atypical nuclei and superficial squamous epithelial cells than in the basal cells. PCNA staining was increased in intensity in the high-grade dysplasias relative to normal basal layer cells. Combined analysis of esophagin and PCNA appears to reveal an inverse relationship between proliferation and differentiation during esophageal neoplastic progression. Moreover, this combined staining approach also offers promise for detecting esophageal cancer in early, precancerous stages.     

p53 gene mutations in Barrett's epithelium and esophageal cancer

Genomic DNA was extracted from archival pathology specimens comprising 10 squamous and 14 adenocarcinomas, including 7 with Barrett's epithelium adjacent to tumor, and corresponding normal esophagus from the resection margin. The polymerase chain reaction was used to amplify selected exons of p53 which were analyzed for mutations using single-strand conformation polymorphism analysis. Mutations were localized to exon 8 for 1 adenocarcinoma and to exon 5 for 1 squamous tumor and 4 of 7 Barrett's specimens. Sequencing confirmed mutations at codons 273 (CGT----CAT; adenocarcinoma) and 176 (TGC----TTC; squamous) and in Barrett's epithelium at codons 152 (CCG----CTG), 155 (ACC----GCC) and 175 (CGC----CAC). Specimens of Barrett's epithelium from separate sites had identical p53 mutations suggesting a clonal origin. Cancers arising in mutant epithelium did not have mutations corresponding to those found in the Barrett's specimens suggesting that other events are required for tumorigenesis.     

Immunohistochemical localization of glutathione S-transferase alpha and pi in human esophageal squamous epithelium, Barrett's epithelium and carcinoma.

High tissue levels of glutathione S-transferases (GSTs), a family of detoxification enzymes, are inversely correlated with cancer risk in the human gastrointestinal tract. Patients with Barrett's esophagus, wherein squamous epithelium is replaced by columnar epithelium, have an increased risk for developing esophageal adenocarcinoma. Biochemical analyses revealed that Barrett's epithelium contains lower levels of GST enzyme activity as well as some GST isoforms, as compared with squamous epithelium. So far, little information on the immunohistochemical distribution of the GST alpha and pi isoforms in normal squamous epithelium, in Barrett's metaplastic epithelium or in adeno- and squamous cell carcinomas of the esophagus is available. Tissues were fixed in formalin and embedded in paraffin. Three 4 microm thick sections were used for hematoxylin and eosin staining and for immunostaining with antibodies against GST alpha and pi. GST alpha and pi were seen in normal squamous epithelium (0% and 75%, respectively), Barrett's epithelium (75% and 100%), adenocarcinoma (25% and 100) and squamous cell carcinoma (27% and 91%). Staining was mainly cytoplasmic, though some nuclear staining with the GST pi antibody was apparent. The varying expression of GST alpha and pi in normal and (pre)neoplastic esophagus may have consequences for the treatment of these diseases and may contribute to an understanding of the development of these esophageal disorders.     

Analysis of Ki-67, p53 and Bcl-2 expression in the dysplasia-carcinoma sequence of Barrett's esophagus.

The grading of dysplasia in Barrett's esophagus has prognostic importance, however observer variation limits the reliability of simple histological analysis alone. We investigated Ki-67, p53 and Bcl-2 expression in Barrett's esophagus, in the sequence from Barrett's low-grade dysplasia to high-grade dysplasia and infiltrating adenocarcinoma. Forty-four esophagectomy specimens were utilized: 39 specimens with esophageal dysplasia and adenocarcinoma and 5 specimens with esophageal dysplasia only. This gave 83 sections (2 sections for specimens with dyplasia and carcinoma) examined from 44 patients. The sections were examined for Ki-67, p53 and Bcl-2 reactivity by immunohistochemistry. Low-grade dysplasia was present in 14 sections, high-grade dysplasia in 30 sections and carcinoma in 39 sections. Ki-67 expression occurred in 2 out of 14 (14%) sections with low-grade dysplasia, in 22 out of 30 (73%) sections with high-grade dysplasia and in 34 out of 39 (87%) sections with carcinoma (p<0.001). p53 protein expression was found in 1 of 14 (7%) sections with low-grade dysplasia, in 18 of 30 (60%) sections with high-grade dysplasia and in 33 of 39 (85%) sections with carcinoma (p<0.001). Expression of Bcl-2 was found in 11 of 14 (84%) sections with low-grade dysplasia but immunoreactivity was not seen in any section with high-grade dysplasia or Barrett's carcinoma. Our results indicate that overexpression of Ki-67, Bcl-2 protein and p53 mutations can be identified as early events during neoplastic progression in Barrett's esophagus. These data support the hypothesis that, in the progression of Barrett's metaplasia to adenocarcinoma, the balance of proliferation/apoptosis plays an important role.     

Immunohistochemical Localization of Glutathione S-Transferase α and π in Human Esophageal Squamous Epithelium, Barrett's Epithelium and Carcinoma

High tissue levels of glutathione S-transferases (GSTs), a family of detoxification enzymes, are inversely correlated with cancer risk in the human gastrointestinal tract. Patients with Barrett's esophagus, wherein squamous epithelium is replaced by columnar epithelium, have an increased risk for developing esophageal adenocarcinoma. Biochemical analyses revealed that Barrett's epithelium contains lower levels of GST enzyme activity as well as some GST isoforms, as compared with squamous epithelium. So far, little information on the immunohistochemical distribution of the GST α and π isoforms in normal squamous epithelium, in Barrett's metaplastic epithelium or in adeno- and squamous cell carcinomas of the esophagus is available. Tissues were fixed in formalin and embedded in paraffin. Three 4 μm thick sections were used for hematoxylin and eosin staining and for immunostaining with antibodies against GST α and π. GST α and π were seen in normal squamous epithelium (0% and 75%, respectively), Barrett's epithelium (75% and 100%), adenocarcinoma (25% and 100%) and squamous cell carcinoma (27% and 91%). Staining was mainly cytoplasmic, though some nuclear staining with the GST π antibody was apparent. The varying expression of GST α and π in normal and (pre)neoplastic esophagus may have consequences for the treatment of these diseases and may contribute to an understanding of the development of these esophageal disorders.     

17p allelic deletions and p53 protein overexpression in Barrett's adenocarcinoma.

Barrett's esophagus is a condition in which the stratified squamous epithelium of the esophagus is replaced by metaplastic columnar epithelium that predisposes to the development of esophageal adenocarcinoma. Allelic deletions of 17p and alterations of p53 including elevated p53 protein levels have been observed in many different tumors. To investigate the presence of 17p allelic deletions and p53 protein overexpression in Barrett's adenocarcinomas, we have combined the use of restriction fragment length polymorphism analysis, multiparameter flow cytometry, and DNA content cell sorting. The combined use of these methodologies permits the purification of aneuploid tumor cells for restriction fragment length polymorphism analysis of 17p allelic deletions and the evaluation of p53 protein expression by multiparameter flow cytometry in the same aneuploid tumor cell populations. We analyzed 15 aneuploid populations and one tetraploid populations from 13 Barrett's adenocarcinomas for 17p allelic deletions and p53 protein overexpression to determine whether both of these alterations are involved in carcinogenesis in Barrett's esophagus. Twelve of 13 tumors (92%) had 17p allelic deletions, and 8 of 13 tumors (62%) had p53 protein overexpression. Eight of the 12 tumors (67%) with 17p allelic deletions also had p53 protein overexpression. These data indicate that both 17p allelic deletions and p53 protein overexpression are frequently involved in carcinogenesis in Barrett's esophagus.     

Progression of Barrett's metaplasia to adenocarcinoma is associated with the suppression of the transcriptional programs of epidermal differentiation

We did expressional profiling on 24 paired samples of normal esophageal epithelium, Barrett's metaplasia, and esophageal adenocarcinomas. Matching tissue samples representing the three different histologic types were obtained from each patient undergoing esophagectomy for adenocarcinoma. Our analysis compared the molecular changes accompanying the transformation of normal squamous epithelium with Barrett's esophagus and adenocarcinoma in individual patients rather than in a random cohort. We tested the hypothesis that expressional profiling may reveal gene sets that can be used as molecular markers of progression from normal esophageal epithelium to Barrett's esophagus and adenocarcinoma. Expressional profiling was done using U133A GeneChip (Affymetrix), which represent approximately two thirds of the human genome. The final selection of 214 genes permitted the discrimination of differential gene expression of normal esophageal squamous epithelium, Barrett's esophagus, and adenocarcinoma using two-dimensional hierarchical clustering of selected genes. These data indicate that transformation of Barrett's esophagus to adenocarcinoma is associated with suppression of the genes involved in epidermal differentiation, including genes in 1q21 loci and corresponding to the epidermal differentiation complex. Correlation analysis of genes concordantly expressed in Barrett's esophagus and adenocarcinoma revealed 21 genes that represent potential genetic markers of disease progression and pharmacologic targets for treatment intervention. PCR analysis of genes selected based on DNA array experiments revealed that estimation of the ratios of GATA6 to SPRR3 allows discrimination among normal esophageal epithelium, Barrett's dysplasia, and adenocarcinoma.     

Mucin gene expression and cell differentiation in human normal, premalignant and malignant esophagus

Esophageal carcinoma includes squamous cell carcinoma and Barrett's adenocarcinoma. The latter usually develops from a premalignant lesion named Barrett's esophagus. MUC genes are known to be specifically expressed in the normal, premalignant and malignant epithelia of various tissues. The aim of this study was to establish the pattern of MUC gene expression in the esophageal mucosa under normal conditions, and under pathological conditions such as squamous cell carcinoma, Barrett's esophagus and adenocarcinoma. Samples of esophageal control mucosa, metaplastic and malignant tissues were obtained from 40 patients undergoing esophagectomy for squamous cell carcinoma (n = 17), or Barrett's esophagus with adenocarcinoma (n = 23). In situ hybridization and northern blot were used with probes specific for the MUC1, MUC2, MUC3, MUC4, MUC5AC, MUC5B, MUC6 and MUC7 genes to assess their expression in these samples. Submucosal glands of control esophageal mucosa expressed MUC5B, whereas MUC1 and MUC4 were found in both control epithelium and squamous cell carcinoma. MUC4 expression correlated with squamous cell differentiation. Barrett's adenocarcinoma exhibited various patterns of MUC gene expression, the strongest being in the well-differentiated mucinous adenocarcinomas. Barrett's metaplasia was also associated with a specific MUC gene expression pattern, since the gastric apomucin mRNAs, MUC5AC and MUC6, were expressed in gastric metaplasia, and the intestinal apomucin mRNAs, MUC3, MUC4 and mostly MUC2, in intestinal metaplasia. Residual expression of gastric apomucin mRNAs was found in intestinal metaplasia. From these results, we conclude that MUC genes can be considered reliable phenotypic markers of the esophageal cell differentiation, thus providing new insight into the development of Barrett's esophagus.     

Neosquamous epithelium does not typically arise from Barrett's epithelium.

PURPOSE: Neosquamous epithelium (NSE) can arise within Barrett's esophagus as a consequence of medical or surgical acid reduction therapy, as well as after endoscopic ablation. Morphologic studies have suggested that NSE can develop from adjacent squamous epithelium, submucosal gland ducts, or multipotent progenitor cell(s) that can give rise to either squamous or Barrett's epithelium, depending on the luminal environment. The cells responsible for Barrett's epithelium self-renewal are frequently mutated during neoplastic progression. If NSE arises from the same cells that self-renew the Barrett's epithelium, the two tissues should be clonally related and share genetic alterations; if NSE does not originate in the self-renewing Barrett's, NSE and Barrett's esophagus should be genetically independent. EXPERIMENTAL DESIGN: We isolated islands of NSE and the surrounding Barrett's epithelium from 20 patients by microdissection and evaluated each tissue for genetic alterations in exon 2 of CDKN2A or exons 5 to 9 of the TP53 gene. Nine patients had p16 mutations and 11 had TP53 mutations within the Barrett's epithelium. RESULTS: In 1 of 20 patients, a focus of NSE had a 146 bp deletion in p16 identical to that found in surrounding Barrett's epithelium. The NSE in the remaining 19 patients was wild-type for p16 or TP53. CONCLUSION: Our mutational data support the hypothesis that, in most circumstances, NSE originates in cells different from those responsible for self-renewal of Barrett's epithelium. However, in one case, NSE and Barrett's epithelium seem to have arisen from a progenitor cell that was capable of differentiating into either intestinal metaplasia or NSE.     

Prospective study of cyclin D1 overexpression in Barrett's esophagus: association with increased risk of adenocarcinoma

BACKGROUND: Esophageal adenocarcinoma commonly arises from a precancerous condition, Barrett's esophagus, in which the normal squamous epithelium is replaced by a columnar cell-lined epithelium. Genetic alterations occurring in this process could serve as biomarkers for the risk of malignant progression, improve surveillance, and contribute to early diagnosis. We examined two potential biomarkers, cyclin D1 and p53, in a prospective cohort of Barrett's esophagus patients. METHODS: A total of 307 patients were enrolled in an endoscopic surveillance cohort, and esophageal biopsy specimens were collected at each endoscopy. Incident cases of adenocarcinoma were matched to control patients within the cohort by duration of follow-up, age, sex, and length of columnar cell-lined epithelium at recruitment. Biopsy specimens were analyzed for cyclin D1 and p53 protein levels by immunohistochemistry. Statistical tests were two-sided. RESULTS: A total of 12 cases of adenocarcinoma occurred within the follow-up period, and tumor biopsy specimens from 11 cases stained positive for cyclin D1. Biopsy specimens from eight of these patients taken at recruitment also stained positive for cyclin D1. A case-control analysis of biopsy specimens obtained at recruitment revealed a statistically significantly increased risk of progression to adenocarcinoma in Barrett's esophagus patients whose biopsy specimens were cyclin D1 positive (odds ratio [OR] = 6. 85; 95% confidence interval [CI] = 1.57-29.91; P =.0106) but not in patients whose biopsy specimens were p53 positive (OR = 2.99; 95% CI = 0.57-15.76; P =.197). CONCLUSIONS: Cyclin D1-positive staining could be a useful biomarker in identifying Barrett's esophagus patients at high risk of esophageal adenocarcinoma. Given the complexity of genetic alterations in the natural history of this cancer, additional biomarkers will be required to increase the sensitivity and specificity of molecular diagnosis.     

p53 protein expression and cell proliferation in non-neoplastic and neoplastic proliferative skin diseases

AIMS AND BACKGROUND: The p53 protein is essential for the regulation of cell proliferation and its aberrant accumulation is usually seen in malignant tumors but also occurs in squamous epithelium of inflammatory skin diseases characterized by hyperproliferation. The aim of this study is to elucidate the role of the p53 tumor suppressor protein in the pathogenesis of different hyperproliferative, non-malignant and malignant skin diseases, and to determine the association between p53 overexpression and cell proliferation. We also investigated the influence of aging on p53 and Ki-67 protein expression. METHODS: One hundred and fifty skin specimens divided into 30 samples each of normal skin (NS), psoriatic skin (PS), keratoacanthomas (KA), basal cell carcinomas (BCC), and squamous cell carcinomas (SCC) were examined immunohistochemically to assess p53 and Ki-67 protein expression. RESULTS: p53 immunostaining of NS, PS, KA, BCC and SCC was detected in 39.0%, 46.7%, 66.7%, 80% and 86.7% of cases, respectively. Median values and ranges of p53 protein expression were as follows: 0.0% (range, 0.0-1.8%) in NS, 0.0% (range, 0.0-6.5%) in PS, 9.2% (range, 0.0-24.0%) in KA, 19.3% (range, 0.0-48.1%) in BCC and 30.1% (range, 0.0-68.1%) in SCC. p53- and Ki-67-positive cells were present in basal (NS) and suprabasal layers (PS), and not only in cancer nests of KA, BCC and SCC but also in dysplastic and even morphologically normal epidermis adjoining cancers. The positivity of p53 and Ki-67 proteins differed significantly among the groups, with no differences in p53 expression between NS and PS and in Ki-67 expression between PS and KA. Within all groups there was a significant correlation between p53 and Ki-67 expression. Lesion location and patient age, with the exception of location in PS and age in BCC, were significantly related to p53 and Ki-67 expression in all groups. CONCLUSIONS: Our findings suggest that p53 overexpression occurs mainly in neoplastic skin lesions, although it may also occur in squamous epithelium of inflammatory skin diseases such as PS, as well as in normal skin epithelium. It is associated with cell proliferation in normal as well as altered epithelium. p53 protein overexpression is an age-related process and significantly associated with sun exposure, especially in NS and PS but also in KA and SCC. Our findings suggest that Ki-67 rate and p53 protein expression reflect the degree of malignancy in the examined cutaneous neoplasms.     

Clinicopathological and immunohistochemical study of cancer arising from Barrett's esophagus.

In Japan, Barrett's esophageal cancer is a very rare disease. We examined clinicopathologically and immunohistologically 4 patients with Barrett's esophageal cancer who underwent surgical resection in our department. Barrett's esophageal mucosa was classified into 3 types for detailed observation. Specialized columnar epithelium (SCE) remained on the orifice side of carcinoma, and progression to adenocarcinoma was observed in some dysplastic glands. positive findings were detected on p53 immunohistochemical staining, and the ki-67 labeling index was higher than other types. SCE-type Barrett's esophagus may be a precancerous lesion arising prior to the development of adenocarcinoma.     

Epidermal growth factor receptor (EGFR), proliferating cell nuclear antigen (PCNA) and Ki-67 antigen in laryngeal epithelial lesions.

The epidermal growth factor receptor (EGFR), proliferating cell nuclear antigen (PCNA) and Ki-67 immunostaining in paraffin sections from 154 cases of laryngeal squamous cell carcinoma, 25 specimens of normal and hyperplastic laryngeal epithelium, and 21 preneoplastic lesions was examined. The difference of EGFR expression and PCNA score between laryngeal cancer and dysplastic lesions vs normal and hyperplastic epithelium was significant. There was significant difference in Ki-67 score between malignant vs premalignant lesions and normal and hyperplastic epithelium. There was significant correlation between PCNA score and histopathological grading of the tumour. The highest PCNA expression was detected in stage G3. Our findings have shown that PCNA and Ki-67 staining can be used as a marker of cell proliferative activity in laryngeal epithelial lesions. EGFR, PCNA and Ki-67 expression correlate with severity of laryngeal lesions. PCNA immunostaining can aid in estimating the histological grade of malignant lesions.     

Risk factors, DNA damage, and disease progression in Barrett's esophagus.

Esophageal adenocarcinoma develops on a background of Barrett's esophagus. A number of risk factors have been linked to both conditions, including gastroesophageal reflux and smoking. However, the molecular mechanisms by which these factors influence disease progression remain unclear. One possibility is that risk factors generate promutagenic DNA damage in the esophagus. The comet assay was used to measure DNA damage in esophageal (Barrett's and squamous) and gastric mucosa of Barrett's patients with (n = 24) or without (n = 50) associated adenocarcinoma or high-grade dysplasia in comparison with control patients (squamous mucosa) without Barrett's esophagus (n = 64). Patients completed a questionnaire detailing exposure to some of the known risk factors for Barrett's esophagus and adenocarcinoma. In Barrett's esophagus patients, DNA damage was higher in Barrett's mucosa compared with normal esophageal and gastric mucosa (P < 0.001). In addition, the highest quartile of DNA damage in Barrett's mucosa was associated with an increased risk (odds ratio, 9.4; 95% confidence interval, 1.1-83.4; P = 0.044) of developing adenocarcinoma or high-grade dysplasia compared with DNA damage levels in the lowest quartile. Smoking was associated with higher DNA damage in squamous epithelium in all patient groups (P < 0.01) and in Barrett's mucosa (P < 0.05) in Barrett's esophagus patients only. In controls only, current reflux was associated with higher DNA damage, whereas anti-inflammatory drug use resulted in lower levels. Collectively, these data imply a genotoxic insult to the premalignant Barrett's mucosa that may explain the genetic instability in this tissue and the progression to adenocarcinoma. There is an indication for a role for smoking in inducing DNA damage in esophageal mucosa but an understanding of the role of reflux requires further investigation.     

p53蛋白、雌激素受体、孕激素受体在非小细胞肺癌中的表达及临床意义

目的 检测非小细胞肺癌（ＮＳＣＬＣ）中ｐ５３蛋白、雌激素受体（ＥＲ）和孕激素受体（ＰＲ）表达与临床病理和预后的相关性。方法 应用免疫组织化学ＳＰ法检测１４７例ＮＳＣＬＣ癌组织标本中ｐ５３、ＥＲ、ＰＲ的表达。结果 ｐ５３蛋白总阳性率为６１．２％（９０／１４７）,鳞癌、腺癌、鳞腺癌、大细胞癌阳性率分别为６３．５％（４０／６３）、５７．６％（３３／６６）、６６．７％（１０／１４）、５０％（２／４）。腺癌     

Identification of intestinal-type Barrett's metaplasia by using the intestine-specific protein villin and esophageal brush cytology

Villin is an actin-binding cytoskeletal protein required for brush-border formation in the normal small intestinal and renal proximal tubule epithelium. Villin is a marker of cell differentiation in small intestinal and renal cell lineages, and recent studies have shown villin to be highly expressed in 100% of intestinal-type Barrett's metaplasias. This epithelium is the single greatest risk factor for developing esophageal adenocarcinoma and arises when the normal esophageal squamous epithelium is replaced by a small intestine-like columnar epithelium after damage by chronic gastroesophageal reflux. In intestinal-type Barrett's metaplasia, the villin protein exhibits a highly characteristic staining pattern in which strong apical, brush-border staining of columnar epithelial cells is observed. In this study, the ability to identify intestinal metaplastic cells by using this distinct villin staining pattern was examined in endoscopic esophageal brushings from patients with confirmed Barrett's metaplasia. Esophageal brushings from 81% (17 of 21) of patients with Barrett's metaplasia demonstrated individual columnar cells with the characteristic villin staining pattern, whereas all normal esophageal squamous cells, blood cells, and gastric columnar cells were negative for villin expression. Northern blot analysis demonstrated villin mRNA expression in Barrett's metaplasia but not in the normal squamous esophagus or gastric mucosa from the same patients. The combined use of villin immunohistochemical analysis and esophageal brush cytology may provide a simple and effective method of detecting intestinal-type Barrett's metaplasia in patients at higher risk for developing this epithelium, such as those experiencing chronic gastroesophageal reflux symptoms.     

Barretts carcinoma in a 25-year-old man with point mutation of the p53 tumor suppressor gene

Barrett's esophagus is a recognized risk factor for adenocarcinoma of the esophagus. Dysplasia in Barrett's epithelium is considered a precursor to malignancy. Several tumor suppressor genes, including p53, have recently been implicated in the pathogenesis of esophageal adenocarcinoma. However, the interval between the development of Barrett's esophagus, dysplasia, and frank malignancy is usually very long. A case of adenocarcinoma of the esophagus arising from Barrett's esophagus in a 25-year-old man is discussed. Point mutation in exon 8 of p53 was discovered in this patient's tumor and surrounding dysplastic Barrett's mucosa. To our knowledge, this is the youngest reported case of Barrett's-associated esophageal adenocarcinoma in the medical literature. It suggests that acquired somatic mutations in tumor suppressor genes may occur early in life and that these mutations may contribute to the development of dysplasia and cancer in Barrett's esophagus.     

Differential expressions of cyclin-dependent kinase inhibitors (p27 and p21) and their relation to p53 and Ki-67 in oral squamous tumorigenesis

The cyclin-dependent kinase inhibitors p27Kip1 and p21WAF1/Cip1 play important roles in cell-cycle regulation. Although alterations of these genes have been linked to tumorigenesis of several human carcinomas, their involvement in head and neck squamous tumorigenesis is rarely investigated. To determine the role of these genes in the evolution of squamous carcinoma of the head and neck we evaluated their protein expression by immunohistochemistry in non-dysplastic squamous epithelium, premalignant lesions and oral squamous carcinomas. The p53 gene and Ki-67 expressions were correlated with traditional clinicopathologic variables. Our study shows that in histologically non-dysplastic squamous epithelium, p27 expression was noted mainly in superficial differentiated cells, whereas p21, p53 and Ki-67 staining was observed in basal and suprabasal cells. In dysplasia, divergent expression between p27 and p21 was observed: p27 precipitously decreased and p21, p53, and Ki-67 increased with histologic progression. In squamous carcinomas, p27 was mainly expressed in well differentiated tumor cell nests, while the expressions of p21, p53, and Ki-67 were variable in the poorly differentiated tumor areas. A significant inverse relationship between p27 expression and those of p21, p53, and Ki-67 was observed, but no significant association between any of these markers and clinicopathologic factors was noted in this cohort. Our study indicates that: i) down-regulation of p27 and up-regulation of p21 are associated with early progression of HNSC, ii) p21 expression correlates positively with proliferation while p27 correlates positively with cell differentiation and iii) concurrent p27 and p21 expression analysis may allow for better assessment of HNSC progression.