TP53 and p16INK4A, but not H-KI-Ras, are involved in tumorigenesis and progression of pleomorphic adenomas

The putative role of TP53 and p16(INK4A) tumor suppressor genes and Ras oncogenes in the development and progression of salivary gland neoplasias was studied in 28 cases of pleomorphic adenomas (PA), 4 cases of cystic adenocarcinomas, and 1 case of carcinoma ex-PA. Genetic and epigenetic alterations in the above genes were analyzed by Polymerase Chain Reaction/Single Strand Conformational Polymorphism (PCR/SSCP) and sequencing and by Methylation Specific-PCR (MS-PCR). Mutations in TP53 were found in 14% (4/28) of PAs and in 60% (3/5) of carcinomas. Mutations in H-Ras and K-Ras were identified in 4% (1/28) and 7% (2/28) of PAs, respectively. Only 20% (1/5) of carcinomas screened displayed mutations in K-Ras. p16(INK4A) promoter hypermethylation was found in 14% (4/28) of PAs and 100% (5/5) carcinomas. All genetic and epigenetic alterations were detected exclusively in the epithelial and transitional tumor components, and were absent in the mesenchymal parts. Our analysis suggests that TP53 mutations and p16(INK4A) promoter methylation, but not alterations in the H-Ras and K-Ras genes, might be involved in the malignant progression of PA into carcinoma.     

Prognostic significance of p16INK4a alterations and 9p21 loss of heterozygosity in locally advanced laryngeal squamous cell carcinoma

The p16INK4a gene, localized within chromosome 9p21, has been identified as a cyclin-dependent kinase inhibitor and may negatively regulate the cell cycle acting as a tumor suppressor. Genetic alterations involving the 9p21 region are common in human cancers. A consecutive series of 64 untreated patients (median of follow up 53 months) undergoing surgical resection for locally advanced laryngeal squamous-cell carcinomas (LSCCs) has been studied prospectively. Our purpose was to investigate p16 alterations (9p21 allelic loss, hypermethylation and point mutations) and their possible association with clinico-pathological data and flow cytometric variables (DNA-ploidy and S-phase fraction (SPF)), and to determine the possible prognostic role of this gene in these tumors. PCR-based techniques were used for investigating 9p21 loss of heterozygosity (LOH) and methylation promoter status of the p16 gene. p16 mutations were detected by PCR-SSCP (single strand conformation polymorphism) and sequencing. 9p21 LOH was detected in 16/62 (26%) informative tumors, point mutations in 5% (3/64) and hypermethylation in 9% (6/64) of the cases. p16 alterations were significantly associated with high SPF and DNA-aneuploidy. By univariate analysis, poor histologic differentiation, stage IV, DNA-aneuploidy and p16 point mutations proved to be significantly related to quicker relapse, whereas these same factors, and in addition high SPF, 9p21 LOH and any p16 alterations were significantly related to shorter overall survival. By Cox proportional hazards analysis only histologic grade (G3) and p16 point mutations were independently related to both disease relapse and death. Our study has identified p16 point mutations as important biomolecular indicators in LSCCs.     

Morphological and molecular aspects of cancerogenesis in the lung

Morphology and some molecular aspects of hyperplastic (bronchial basal cell hyperplasia and alveolar cell hyperplasia), metaplastic (squamous metaplasia), preneoplastic and early neoplastic (dysplasia in squamous metaplasia, cancer in situ and atypical alveolar cell hyperplasia) changes were studied in 180 lungs resected due to non-small cell lung cancer: 106 cases (58.9%) of squamous cell carcinoma, 42 (23.3%) of adenocarcinoma and 32 (17.8%) of large cell carcinoma. P53 protein and PCNA expressions were detected immunohistochemically (using formalin-fixed, paraffin-embedded sections). DNA extracted from the microdissected P53-positive cells was analysed for point mutations in the P53 gene. No P53 immunostaining was observed in normal mucosa, hyperplasia of basal cells, squamous metaplasia without and with minor and moderate dysplasia of bronchial mucosa as well as alveolar cell hyperplasia. Overexpression of P53 protein occurred in 3 out of 12 (25%) cases of severe bronchial dysplasia, 5 out of 11 (45.5%) cases of intraepithelial carcinoma and 6 out of 45 (13.3%) cases of alveolar cell hyperplasia. Using direct sequencing, mutations in the P53 gene were detected in 11 out of 14 (87%) P53-immunopositive samples, including all severe dysplasias, all carcinomas in situ and 3 of 6 alveolar cell hyperplasias. A significant association was observed between PCNA expression and preinvasive as well as invasive lesions. The data clearly show that lung resected due to primary cancer ought to be treated as "field cancerization" in which one can find early morphologic events of multi-step cancerogenesis. P53 protein alterations and P53 gene mutations can occur before invasion and its frequency depends on the degree of dysplasia.     

p16INK4A and CDH13 hypermethylation in tumor and serum of non-small cell lung cancer patients

Aberrant promoter hypermethylation of several known or putative tumor suppressor genes occurs frequently during the etiopathogenesis of lung cancer and is a promising tool for cancer detection. In the present study, promoter hypermethylation of p16INK4A and CDH13 genes was investigated in tumor tissue and in matched serum from 61 patients with histologically confirmed non-small cell lung cancer. Using a fluorescence-based method of methylation-specific PCR (F-MSP), methylation of p16INK4A and CDH13 was detected in 79% and 66% of tumors, respectively, and was not significantly related to conventional clinicopathological characteristics of patients or tumors. Methylation of both genes was observed in 52% of tumors and of at least one gene in 92% of lesions. In matched serum, hypermethylation of p16INK4A and CDH13 was observed in 26% and 23% of patients, respectively, but as they were not associated, the methylation of at least one gene was detected in 39% of patients. In conclusion, the frequency of p16INK4A or CDH13 hypermethylation in patient serum, together with evidence of their early occurrence in lung cancerogenesis and the total lack of methylation in serum from healthy individuals, offer a promising tool for non invasive early detection of lung cancer.     

p16 Mutation Spectrum in the Premalignant Condition Barrett's Esophagus

Background

Mutation, promoter hypermethylation and loss of heterozygosity involving the tumor suppressor gene p16 (CDKN2a/INK4a) have been detected in a wide variety of human cancers, but much less is known concerning the frequency and spectrum of p16 mutations in premalignant conditions.

Methods and Findings

We have determined the p16 mutation spectrum for a cohort of 304 patients with Barrett''s esophagus, a premalignant condition that predisposes to the development of esophageal adenocarcinoma. Forty seven mutations were detected by sequencing of p16 exon 2 in 44 BE patients (14.5%) with a mutation spectrum consistent with that caused by oxidative damage and chronic inflammation. The percentage of patients with p16 mutations increased with increasing histologic grade. In addition, samples from 3 out of 19 patients (15.8%) who underwent esophagectomy were found to have mutations.

Conclusions

The results of this study suggest the environment of the esophagus in BE patients can both generate and select for clones with p16 mutations.     

Detection of p16 abnormalities in early-stage non-small cell lung cancer

We investigated the clinical significance of p16 abnormalities (mutations by sequencing and hypermethylation by methylation-specific PCR) in 52 radically resected stage I-II non-small cell lung cancers (NSCLCs). P16 abnormalities were detected in 20 (38%) patents (point mutations in 4 (8%) and promoter hypermethylation in 16 (31%) cases. No correlation was found between p16 abnormalities and various clinicopathologic factors, including sex, histological type of tumor and TNM (I vs. II) stage. The multivariate analysis of survival was performed using the Cox proportional hazard model. When the types of 16 inactivation were analyzed, p16 hypermethylation rather than point mutation was associated with poor Prognosis. The presented results prompt the conclusion that hypermethylation of p16 is the major mechanism for p16 gene inactivation in early stage NSCLC and could be a useful molecular marker for the prognosis.     

Expression of matrix metalloproteinase-9 (gelatinase B) in benign, premalignant and malignant laryngeal lesions

The matrix metalloproteinases (MMPs) are a family of proteolytic zinc-containing enzymes, which are responsible for the breakdown of the extracellular matrix components in pathological and physiological conditions. They are involved in basement membrane disruption, stroma and blood vessel penetration, metastasis and more recently there is evidence that they participate in tumor growth and angiogenic events. Matrix metalloproteinase 2 and 9 (MMP 2 and 9) belong to the gelatinases, a subgroup of MMPs, and have the capacity to degrade the triple helix type IV collagen of basal lamina of the basement membrane. With the present study, we tried to demonstrate the expression of MMP-9 immunohistochemically, comparatively in benign, premalignant and malignant lesions of the larynx. We studied 154 laryngeal lesions including 55 squamous cell carcinomas, 8 in situ carcinomas, 54 cases of dysplasia (of low and intermediate grade), 13 papillomas and 24 cases of keratosis. Overexpression of MMP 9 was observed in 74.4% and 50% in invasive and in situ squamous cell carcinomas respectively. In dysplastic cases, in papillomas and in keratoses the percentage of overexpression was 62.9%, 61.53% and 54.16% respectively and the expression of MMP-9 was significantly higher in invasive squamous cell carcinomas compared to dysplasias (p=0.000004). Also significantly higher was the expression of MMP-9 in dysplastic cases compared to papillomas (p=0.023). The MMP-9 expression was related neither to survival nor to the other available clinicopathological parameters (tumor size, grade, clinical stage, lymph node status and patient age). In conclusion, our study indicates that the expression of MMP-9 is up-regulated in a stepwise fashion, with two main steps, the first one, when a dysplastic lesion evolves and the next one, when the dysplasia progresses to invasive carcinoma.     

No mutations found in exon 2 of gene p16CDKN2A during rat tongue carcinogenesis induced by 4-nitroquinoline-1-oxide

The medium-term tongue carcinogenesis assay is a useful model for studying oral squamous cell carcinomas phase by phase. The present study aimed to investigate mutations in exon 2 of gene p16CDKN2A during rat tongue carcinogenesis induced by 4-nitroquinoline 1-oxide (4NQO) using direct DNA-sequencing method. A total of 30 male Wistar rats were treated with 4-nitroquinoline 1-oxide (4NQO) in drinking water for 4, 12, and 20 weeks at 50 ppm dose. Ten animals were used as negative control. No histopathological changes in tongue epithelia were observed among controls or in the group treated for 4 weeks with 4NQO. Following 12-week treatment, hyperplasia and epithelial dysplasia were found in mild and moderate forms. At 20 weeks, the tongue presented moderate and/or severe oral dysplasia and squamous cell carcinoma, with squamous cell carcinoma in the majority of animals. No mutations were found in any experimental period evaluated that corresponded to normal oral mucosa, hyperplasia, dysplasia and squamous cell carcinomas. Taken together, our results suggest that p16CDKN2A mutations in exon 2 are not involved in the multistep tongue carcinogenesis of Wistar rats induced by 4NQO.     

Comparison of the pick-and-smear and Saccomanno methods for sputum cytologic analysis

The two methods of preparing sputum specimens for cytologic study, the (fresh) pick-and-smear technique and the (blended) Saccomanno technique, were compared using 249 consecutive specimens. Two slides were prepared for each specimen by each technique. Of the specimens, 103 showed squamous metaplasia, carcinoma in situ or carcinoma. A semiquantitative rating system (0 to 4+) was used to determine the number of diagnostic cells for each method for those 103 cases. More diagnostic cells were found on the Saccomanno preparations (217) than on the fresh preparations (154). There were 121 diagnostic cells in the Saccomanno preparations versus 95 diagnostic cells in the fresh preparations from 63 squamous metaplasias; 7 versus 3 for the preparations from 5 carcinomas in situ; 64 versus 42 from 28 squamous cell carcinomas; 3 versus 1 from 1 large cell undiffernomas; and 12 diagnostic cells in Saccomanno preparations versus 5 in fresh preparations from 3 small cell cancers. Twelve squamous metaplasias, two carcinomas in situ, four squamous carcinomas, one adenocarcinoma and one small cell cancer had no diagnostic cells on the fresh preparations; four squamous metaplasias and one squamous carcinoma had no diagnostic cells on the Saccomanno preparations. More diagnostic information and fewer false-negative results were achieved with the Saccomanno technique.     

Prevalence of aberrant methylation of p14ARF over p16INK4a in some human primary tumors

The INK4a/ARF locus encodes two unrelated tumor suppressor proteins, p16INK4a and p14ARF, which participate in the two main cell-cycle control pathways, p16–Rb and p14–p53. Methylation of CpG promoter islands has been described as a mechanism of gene silencing. Exon 1 of the p16INK4a gene and the p14ARF promoter gene reside within CpG islands. Therefore, both can become methylated de novo and silenced. It has recently been proposed that the methylation changes in certain genes could be used as molecular markers for the detection of almost all forms of human cancer. Here, we analyzed concomitantly in each tumor sample and normal tissue the methylation status of p16INK4a and p14ARF by methylation-specific PCR (MSP) in 100 breast, 95 colon and 27 bladder carcinomas. A series of clinicopathological parameter were obtained from the medical records of the patients, p14ARF showed a higher rate of hypermethylation than p16INK4a in all three tumor types. p16INK4a and p14ARF aberrant methylation was significantly correlated with poor prognosis clinicopathological parameters of the three tumor types. We conclude that both p16INKa and p14ARF hypermethylation may be involved in breast, colon and bladder carcinogenesis, with special emphasis on the role of the lesser studied p14ARF gene, and that tumors with aberrant methylation in the two genes were associated with worse prognosis.     

Glycoprotein CD44 expression in benign, premalignant and malignant epithelial lesions of the larynx: an immunohistochemical study including correlation with Rb, p53, Ki-67 and PCNA.

CD44 is an integral membrane glycoprotein that has diverse functions in cell-cell and cell-substrate interactions. It has been suggested that it may be a determinant of metastatic and invasive behavior in carcinomas. The immunohistochemical expression of CD44 was examined in a series of 34 squamous cell carcinomas, 13 in situ carcinomas, 35 cases with various degrees of epithelial dysplasia, 10 papillomas and 17 cases of keratosis. We used the monoclonal mouse anti-human phagocytic glycoprotein-1 CD44 (clone DF 1485), on formalin-fixed, paraffin-embedded tissue. CD44 expression was correlated with the expression of Rb and p53 proteins, with the proliferative indices Ki-67 and PCNA as well as with conventional clinicopathological data. The mean value of CD44 expression was 78.84 in squamous cell carcinomas, 78.04 in situ carcinomas, 54.93 in dysplasia, 26.8 in papillomas and 24.97 in keratosis. There was no significant difference of CD44 expression between in situ and invasive carcinomas. However, a strong difference of reaction between carcinomas and the other cases was observed. CD44 expression was statistically higher in dysplastic lesions than the cases of keratosis (p < 0.0001) and papillomas (p = 0.01). In the group of invasive carcinomas, CD44 expression was statistically correlated with pRb (p = 0.011), while in preinvasive lesions it was correlated with PCNA (p = 0.016). The relationship with the degree of dysplasia or grade of carcinoma and p53 protein expression was insignificant. These observations suggest that CD44 expression may be involved in the multiple mechanism of the development and progression of laryngeal lesions and may help to predict the risk of transformation of the benign or precancerous lesions to cancer.     

Inactivation of p16INK4a in Primary Tumors and Cell Lines of Head and Neck Squamous Cell Carcinoma

Inactivation of the p16^INK4a gene by mutation and deletion is common in head and neck squamous cell carcinoma (HNSCC). The present study demonstrates that hypermethylation of the 5 CpG islands can serve as an alternative mechanism for the inactivation of the p16^INK4a gene in this tumor. We studied 11 HNSCC cell lines and 17 oral squamous cell carcinoma (OSCC) primary tumors for p16^INK4a gene status by protein/mRNA and DNA genetic/epigenetic analyses to determine the incidence of its inactivation. Our study indicates that: (1) inactivation of p16 protein is frequent in HNSCC cell lines (6/11, 54.5%) and OSCC primary tumors (15/17, 88.2%), (2) inactivation of p16^INK4a protein is commonly associated with the presence of gene alteration such as mutation, homozygous deletion and especially aberrant methylation, and (3) genomic sequencing of bisulfite-modified DNA shows that the carcinoma develops a heterogeneous pattern of hypermethylation.     

p16 Expression in Squamous Lesions of the Female Genital Tract

The aim of this study was to examine the role of p16 in the pathogenesis of squamous carcinoma of the gynecologic tract. Squamous carcinoma and carcinoma in situ from the female genital tract were examined for the expression of p16 by paraffin immunohistochemistry. About 74% (40/54) of cases showed p16 expression. By primary site, 77% (23/30) of cervical, 67% (6/9) of vaginal and 85% (11/13) of vulvar primaries expressed p16, but two endometrial primary squamous carcinomas were negative (0/2). In addition, p16 was not identified in non-dysplastic tissue and low grade dysplasia. In cases where there were matched vaginal or vulvar and cervical primaries in a given patient, there was concordant positive p16 expression. It is concluded that p16 is frequently expressed in squamous carcinoma of the cervix, vagina and vulva, but not seen in cases of benign and low grade lesions. It may be a marker of transformation from a low to a high grade lesion. More cases of endometrial primaries need to be studied to see if these evolve by a p16-independent pathway.     

P16(INK4a) immunocytochemistry in liquid-based cytology samples in equivocal Pap smears: added value in management of women with equivocal Pap smear

OBJECTIVE: To test whether p1l6(INK4a) immunocytochemistry (ICC) in liquid-based cytology (LBC) is useful with colposcopy in abnormal Pap smears. STUDY DESIGN: A series of 248 women with abnormal Pap smear were analyzed for oncogenic (HR) human papillomavirus (HPV) types using the Hybrid Capture II assay and for p16(INK4a) expression using ICC on cervical samples in PreservCyt liquid media. Colposcopic and loop electrosurgical excision procedure (LEEP) cone biopsy were the gold standard. RESULTS: p16(INK4a) ICC did best as predictor of high-grade squamous intraepithelial lesion, with OR 12.18 (2.72-54.57) (p = 0.0001), showing 88.2% sensitivity (SE), 61.9% specificity (SP), 14.6% positive predictive value (PPV) and 98.6% negative predictive value (NPV). In sorting discrepant cases, p16(INK4a) ICC results in 100% SE and 100% NPV in detecting cervical intraepithelial neoplasia (CIN) 2 lesions among Pap+/biopsy- women. In atypical squamous cells undetermined significance (ASCUS) cytology, adding p16(INK4a) ICC improves specificity of colposcopy from 27.3% to 81.8% and PPV from 42.8% to 71.4%. Best performance is obtained with p16(INK4a) ICC and colposcopy: 83.3% SE, 81.8% SP, 71.4% PPV and 90.0% NPV. CONCLUSION p16(INK4a) is useful in sorting clinically relevant discrepant cases, and p16(INK4a) ICC significantly improves SP and PPV of colposcopy in management of ASCUS cytology.     

Evaluation of p16INK4a in cervical lesion of premenopausal and postmenopausal women

Pap smears of postmenopausal women are often misdiagnosed because of the difficulty in distinguishing atrophic epithelial cells groups only by morphological criteria. In this study we investigated the diagnostic application of immunocytochemical staining of p16INK4a on conventional Pap smear. A total of 137 cervical specimens were enrolled in this study, of which 77 and 60 cervical smears were taken from premenopausal and postmenopausal women, respectively. Two cervical smears were taken simultaneously in 68 women, one for conventional cytology and the other for immunostaining. Additional 69 cervical smears were taken from the archive, decolorized and then used for immunostaining. In premenopausal women 1 out of 14 (7.1%) with negative cytology, 7 out of 24 (29.2%) with low grade squamous intra-epithelial lesion (LSIL), all 35 (100%) with high grade squamous intraepithelial lesion (HSIL) and all 4 (100%) with squamous cell carcinoma (confirmed by histopathology) had positive staining to p16INK4a. In postmenopausal women p16INK4a positivity was observed in 4 out of 7 (57.1%) cases of LSIL, 12 out of 14 (85.7%) cases of HSIL and all 4 out of 5 (80%) different cases of carcinoma (1 cervical adenosquamous carcinoma and 3 cervical squamous cell carcinoma in situ confirmed by histopathology), but none of 34 smears with normal cytology. Twenty smears with normal cytology chosen for the negative control in this study were from the group of postmenopausal women and were as expected negative for p16INK4a immunostaining. In the group of postmenopausal women, 16 out of 60 (26.7%) cases the cytological diagnosis was established on the basis of pl6lNK4a immunostaining as being HSIL. From our preliminary study on a limited number of samples, we can however conclude that pl6INK4a immunostaining is a very useful tool for cytological diagnosis enabling to distinguish HSIL from normal, reactive or inflammatory changes.     

Morphologic characteristics of p16INK4a-positive cells in cervical cytology samples

OBJECTIVE: Overexpression of p16INK4a has been proposed as a biomarker helpful for the identification of dysplastic cervical epithelial cells on histologic slides as well as in cervical smears. Since a few nontransformed cells in the genital tract in some instances may also express p16INK4a, we evaluated whether applying established morphologic criteria for cervical dysplasia allows a distinction of dysplastic from nondysplastic p16INK4a-stained cells in cytologic samples. STUDY DESIGN: Liquid-based cytology samples were obtained from a screening population (n=50), and from patients attending a dysplasia clinic (n=40). Slides prepared from these samples were stained with the conventional Papanicolaou stain procedure. From each specimen, a second slide was prepared in parallel and immunostained for p16INK4a. Cytologic diagnoses for most patients attending the dysplasia clinic could be compared to the reported histologic diagnoses on punch biopsy samples taken from the patients at the time of colposcopy. This allowed a comparison of the cytology and p16INK4a immunostaining results with subsequent hematoxylin and eosin-based histologic diagnoses. RESULTS: Overall, in 10% of slides obtained from patients with nonsuspicious smears, few p16INK4a-positive cells were found. Using established morphologic criteria and applying these criteria on cells showing any p16INK4a immunoreactivity, p16INK4a-positive normal or metaplastic cells could be discriminated from p16INK4a-expressing dysplastic cells. In 21 of 22 cases (95%) of high grade lesions (cervical intraepithelial neoplasia 2 or higher in follow-up histology), easily recognizable p16INK4a-positive dysplastic cells could be detected, with the remaining case lacking dysplastic cells in the thin-layer slide used for p16INK4a immunostaining. CONCLUSION: Established morphologic criteria for cervical dysplasia can be readily applied to p16INK4a-immunostained cytologic specimens. Thus, p16INK4a immunostaining may help to avoid ambiguities in the interpretation of cervical cytology samples and facilitate more rapid diagnosis and possibly even automated screening of cytologic slides.     

Methylation of E-cadherin and hMLH1 genes in Indian sporadic breast carcinomas

Hypermethylation of promoter regions leading to inactivation of tumor suppressor genes is a common event in the progression of several tumor types. We have employed a novel restriction digestion based multiplex PCR assay to analyse the methylation status of promoter regions of tumor suppressor genes (p16, hMLH1, MGMT and E-cadherin) in sporadic breast carcinomas of Indian women. The present results indicated the absence of hypermethylation in promoter region of p16 and MGMT genes. However, 6 of the 19 (31.6%) sporadic breast carcinomas showed hypermethylation in the promoters of two of the genes analysed; three in hMLH1 and another three in E-cad. Since our earlier studies have shown lack of genetic alterations such as missense mutations and deletions in the tumor associated genes-p16, ras and p14ARF in sporadic breast tumors, the epigenetic alterations of the two genes reported in the present study could be of interest and might be among the events in the genesis/progression of sporadic breast carcinomas.     

Proliferating activity in oral dysplastic leasions and squamous cell carcinomas

The aim of the study was the quantitative analysis of AgNORs in oral squamous cell carcinomas as well as in dysplastic epithelial changes accompanied and not accompanied by oral squamous cell carcinomas. AgNOR proteins were visualized in histological slides using silver impregnation technique according to D. Ploton. In each sample 100 cell nuclei were assessed. The study used 54 cases of proliferating oral epithelial changes divided into 3 groups: group I consisting of 13 cases of dysplastic lesions not accompanied by oral squamous cell carcinomas; group II (a total of 18 cases) containing dysplastic lesions situated in the vicinity of oral carcinomas and group III (23 cases) with oral squamous cell carcinomas. Statistically significant differences were found between groups with mild dysplasia and groups with severe dysplasia as well as squamous cell carcinomas. Statistical analysis did not show any differences in the number of AgNORs between squamous cell carcinomas and epithelial lesions with severe dysplasia. Our results demonstrate that the analysis of AgNORs expression can serve only as an additional parameter to evaluate the potential of malignant transformation.     

Combined analysis of HPV DNA and p16INK4a expression to predict prognosis in ASCUS and LSIL pap smears

Human papillomavirus (HPV) is known to play an important etiological role in the genesis of cervical cancer, but only a very small proportion of infected women develop invasive cervical cancer. The purpose of cervical cancer prevention is early diagnosis of its precursors. The molecular detection of HPV DNA as a diagnostic test to cervical carcinogenesis gave a low positive predictive value as compared to the use of biomarkers. p16INK4a has been proposed as putative surrogate biomarkers that would allow identification of dysplastic cervical epithelia. Serial consecutive cervical smears were test for high-risk HPV stained with immunocytochemistry for p16INK4a and followed-up for 36 months. The aim of the study was to evaluate the immunohistochemical expression of pl6INK4a as a marker of progression risk in low-grade dysplastic lesions of the cervix uteri. In the present series, significant pl6 overexpression was observed in the group that progressed from low to high-grade squamous intraepithelial lesion when compared with the group that did not progress. In conclusion, overexpression of p16INK4a acts as potential biomarkers for cervical cancer progression from premalignant lesions.