Dysplasia in oral lichen planus: relevance, controversies and challenges. A position paper.

BACKGROUND: Patients with oral lichen planus (OLP) have an increased risk of oral cancer. For this reason, OLP is classified as an oral potentially malignant disorder. However, the precise personal (or individual) risk is unknown. Recent meta-analytical studies have reported that dysplastic OLP may transform to cancer in around 6% of cases, while the rate of transformation is lower (<1.5%) in non-dysplastic cases. The presence of epithelial dysplasia has emerged as the most powerful indicator for assessing cancer risk in oral potentially malignant disorders in routine practice. However, the general acceptance of epithelial dysplasia as an accompanying histologic feature in OLP is subject to great controversy. Many pathologists consider the presence of dysplasia as a criterion to exclude OLP when routinely reporting on this disease. This practice, widespread among oral pathology professionals, has resulted in the underestimation of the potential for malignancy of OLP. MATERIAL AND METHODS: A review of the literature was carried out in order to critically analyze the relevance, controversies and challenges encountered across the diagnosis of epithelial dysplasia in OLP. RESULTS: 12 studies have been published examining dysplastic changes in OLP, reporting figures ranging from 0.54% to 25% of cases with dysplasia in the first diagnostic biopsy. The diagnosis of dysplasia in the OLP poses an additional difficulty due to the fact that the affected oral epithelium per se develops changes related to autoimmune aggression. Among the most frequent histological features of OLP that develops dysplasia are basal cell hyperplasia with basaloid appearance, loss of basal cells polarity, cellular and nuclear pleomorphism and irregular stratification. CONCLUSIONS: Epithelial dysplasia should not be considered an exclusion criterion for OLP; its evaluation requires experienced pathologists in this field.

Is oral cancer incidence among patients with oral lichen planus/oral lichenoid lesions underestimated?

BACKGROUND: Oral lichen planus (OLP) and oral lichenoid lesions (OLL) are considered potentially malignant disorders with a cancer incidence of around 1% of cases, although this estimation is controversial. The aim of this study was to analyze the cancer incidence in a case series of patients with OLP and OLL and to explore clinicopathological aspects that may cause underestimation of the cancer incidence in these diseases. METHODS: A retrospective study was conducted of 102 patients diagnosed with OLP (n = 21, 20.58%) or OLL (n = 81) between January 2006 and January 2016. Patients were informed of the risk of malignization and followed up annually. The number of sessions programmed for each patient was compared with the number actually attended. Follow-up was classified as complete (100% attendance), good (75-99%), moderate (25-74%), or poor (<25% attendance) compliance. RESULTS: Cancer was developed by four patients (3.9%), three males and one male. One of these developed three carcinomas, which were diagnosed at the follow-up visit (two in lower gingiva, one in floor of mouth); one had OLL and the other three had OLP. The carcinoma developed in mucosal areas with no OLP or OLL involvement in three of these patients, while OLP and cancer were diagnosed simultaneously in the fourth. Of the six carcinomas diagnosed, five (83.3%) were T1 and one (16.7%) T2. None were N+, and all patients remain alive and disease-free. CONCLUSIONS: The cancer incidence in OLP and OLL appears to be underestimated due to the strict exclusion criteria usually imposed.

Asymmetrical proliferative pattern loss linked to cyclin D1 overexpression during malignant transformation of the lip epithelium.

BACKGROUND: There is inadequate knowledge on the involvement of oncogenic mechanisms linked to the cyclin (CCND1) gene in lip squamous cell carcinoma (LSCC). OBJECTIVE: The aim of this study was to analyse the implication of cyclin D1 in the malignant transformation of lip lesions. METHODS: We immunohistochemically studied 45 actinic cheilitis cases (15 mild dysplasia, 15 moderate dysplasia, 15 severe dysplasia/carcinoma in situ), 30 LSCC cases with adjacent non-tumour epithelium and 15 normal oral epithelium samples for detection of cyclin D1, ß-catenin and Ki-67. RESULTS: Cyclin D1 and Ki-67 expressions were significantly increased in the basal layer of premalignant epithelia and peripheral layers of tumour nests vs. CONTROLS: Premalignant epithelia had lost their asymmetrical proliferative pattern. CONCLUSION: Lip carcinogenesis was associated with loss of the asymmetrical proliferative pattern, a preventive mechanism against lip oncogenesis, and with cyclin D1 overexpression.

Asymmetrical proliferative pattern loss during malignant transformation of the oral mucosa.

OBJECTIVES: The aim of this study was to study the loss of asymmetrical proliferation in oral tumorigenesis. MATERIALS AND METHODS: Samples: 92 oral squamous cell carcinomas (OSCC) with associated non-tumor epithelia (NTE). NTE and tumor were classified as distant from or close to the invasion point. Immunohistochemistry was performed using Mib-1 antibody. Ki-67 was assessed in basal, parabasal layer, medium and upper third, counting total and positive cells. Proliferative patterns were classified according to the ki-67 expression: 1 = expression in parabasal layers of well-differentiated tumor nest (WDTN); 2 = expression in parabasal and basal layers of WDTN; 3 = ki-67 expression in <20% cells in tumor tissue without WDTN; 4 = ki-67 expression in ≥20% of cells in tumor tissue without WDTN; and 5 = ki-67 expression exclusively found in basal layers of WDTN. RESULTS: Ki-67 expression was highest in parabasal layers of both close and distant NTE (39.7 ± 27.6 and 30.1 ± 20) and was also elevated in the close (43.4 ± 21.3) and distant (48.8 ± 21.9) tumor tissue samples. Close tumors largely corresponded to proliferation patterns 2 and 4, while distant tumors generally followed pattern 4. Of the 92 close NTE samples, 23 showed reduced basal proliferation with increased parabasal proliferation. Tumors derived from these epithelia followed patterns 2 (52%, 12/23 cases) or 4 (30.4%, 7/23 cases). Parabasal proliferation in distant NTE was significantly increased in patients with multiple vs. single tumors (36.7% vs. 25.4%; P = 0.032). CONCLUSION: The change from asymmetrical to symmetrical division appears to be an oncogenic mechanism in oral carcinogenesis.

Expression of proliferative markers in ameloblastomas and malignant odontogenic tumors.

OBJECTIVE: To compare the proliferative activity in ameloblastoma and malignant odontogenic tumors, as assessed by Ki-67 immunostaining and determine whether expression of substance P (SP) and NK-1 receptor (NK-1R) is related to cell proliferation in these tumors. MATERIALS AND METHODS: Immunohistochemistry was used to evaluate protein expression in 44 benign and malignant odontogenic tumors from 39 patients. Immunohistochemistry was performed with anti-SP, anti-NK-1R, and anti-Ki-67 monoclonal antibodies, and the clinical and pathological data of the patients with odontogenic tumor were evaluated. RESULTS: Expression of Ki-67 in malignant odontogenic tumors was significantly higher than in ameloblastomas (P < 0.001), and the expression level was associated with higher expression of NK-1R. Among the ameloblastomas, there was significantly higher expression of Ki-67 in peripheral ameloblastic-like cells (3.3 ± 4.1) than in stellate reticulum-like cells (2.6 ± 3.7) (P = 0.04). In the majority of tissue locations of the malignant tumors, expression of SP and NK-1R was positively correlated with higher expression of Ki-67. CONCLUSION: These findings show that the expression level of Ki-67 in ameloblastomas was positively correlated with the rate of growth of odontogenic tumors. Overexpression of NK-1R complex in malignant odontogenic tumors could be part of the trigger stimulus that results in higher proliferative activity of the tumor.

Molecular findings in oral premalignant fields: update on their diagnostic and clinical implications.

The development of multiple oral tumours, seen in up to 30% of patients with a primary oral squamous cell carcinoma, is sometimes attributable to the presence of genetically altered premalignant fields and has important prognostic implications. Molecular techniques available for the definitive diagnosis of such a field (loss of heterozygosity analysis of 3p, 9p and 17p and study of TP53 tumour suppressor gene mutation) are expensive, complex and not universally available, hampering their routine application. Nevertheless, molecular diagnosis is essential for modern assessment of the risk of multiple tumours and for decisions on the appropriate preventive and therapeutic approaches. This article reviews current knowledge on molecular findings in premalignant fields in the oral cavity and oropharynx and provides an update on criteria for their identification, discussing the clinical and therapeutic implications.

Cell apoptosis and proliferation in salivary glands of Sjögren's syndrome.

BACKGROUND: Sjögren's syndrome (SS) occurs associated with parotid neoplasm, non-Hodgkin's B-cell lymphoma, which could impair the condition or be life-threatening for patients. The aim of this work was to analyze cell proliferation and apoptosis modifications in acinar, ductal and inflammatory infiltrate in salivary glands (SG) in patients with Sjögren Syndrome, keratoconjunctivitis, or stomatitis sicca or in healthy subjects, to establish parameters that indicate the likelihood of malignancy of the disease in populations at risk. METHODS: A study was performed with n = 58 histological samples of lower lip SG from patients diagnosed with SS, keratoconjunctivitis, or stomatitis sicca (SICCA) and from healthy subjects (C). Ki67 and caspase-3 immunolabeling were performed. RESULTS: The most important result was significant differences between the three study groups in Ki67 and caspase-3 markers (P < 0.0001) in infiltrated lymphocytes. CONCLUSION: The results of this work are indicative of a high degree of proliferation (85%) in infiltrated lymphocytes (IL) associated with SS which, according the literature, could be considered a risk. Furthermore, the markers used in this work are widely known and represent a lower cost than others and can be used to determine risk groups within the population of SS patients, enabling their follow-up.

Ki-67 expression in non-tumour epithelium adjacent to oral cancer as risk marker for multiple oral tumours.

OBJECTIVE: The aim of this study was to determine whether the differential assessment of epithelial proliferation is useful to diagnose premalignant fields and assess the risk of multiple tumours. MATERIAL AND METHODS: We analysed 83 oral carcinomas with associated non-tumour epithelium classified as distant or close according to its distance (> or <1 cm) from the invasion point, and as squamous hyperplasia, mild, moderate, severe dysplasia or carcinoma in situ. Twenty-five healthy oral mucosa samples were used as controls. An immunohistochemical technique was applied using Mib-1. Ki-67 in premalignant epithelium was assessed in basal layer, parabasal layer, medium and upper third. RESULTS: Parabasal expression was significantly higher or showed a tendency to be higher in close and distant epithelia with any histological grade than in the controls. Parabasal Ki-67 significantly differed between distant epithelia associated with multiple vs single tumours (P < 0.001) and between distant epithelia associated with multiple tumours vs controls (P < 0.001). This difference was not observed between distant epithelia associated with single tumours and controls (P = 0.175). The cut-off point that differentiated epithelia associated with multiple tumours was >50% of Ki-67 + parabasal cells in distant epithelia, which yielded 0.88 sensitivity and 0.79 specificity. CONCLUSIONS: The concept of a precancerous field may be linked to an increase in the proliferative activity of parabasal cells.

A role for the substance P/NK-1 receptor complex in cell proliferation and apoptosis in oral lichen planus.

OBJECTIVES: To determine whether substance P (SP) and NK-1 receptor (NK-1R) are expressed in oral lichen planus (OLP) and are related to cell proliferation and apoptosis in this disease. MATERIAL AND METHODS: Tissue samples from 50 OLP patients and 26 healthy controls were studied. Immunohistochemistry was performed with anti-SP, anti-NK-1R, anti-ki-67 and anti-caspase-3 monoclonal antibodies and the clinical and pathological data of the OLP patients were evaluated. RESULTS: With the exception of NK-1R expression in epithelial cell membrane and cytoplasm, all markers were more frequently present in OLP patients than in controls (P < 0.05). Higher cytoplasmatic expression of NK-1R was associated with higher epithelial expression of caspase-3 (P < 0.05). Higher epithelial expression of NK-1R and SP was associated with higher suprabasal and basal epithelial expression of ki-67 (P < 0.05 and P < 0.005, respectively). CONCLUSIONS: Actions of the SP/NK-1R complex may contribute to the immune disorder underlying OLP and trigger stimuli to induce cell proliferation. These results indicate that this complex might play a role in the malignant transformation of OLP.

Differences in the expression of p53 protein in oral lichen planus based on the use of monoclonal antibodies DO7 and pAb 240.

UNLABELLED: A comparison is made of p53 expression in oral lichen planus, detected via monoclonal antibodies pAb240 and DO7, and with cell apoptosis and proliferation markers. An immunohistochemical study was made of 51 cases of oral lichen planus and 26 controls, using monoclonal antibodies DO7 and pAb240, anti-caspase-3 antibody and Mib-1 antibody against Ki-67. The cases showed important p53 expression with D07 (68%, 36 cases), presumably wild p53, and low p53 expression with pAb240 (14.9%, 7 cases), presumably mutated p53. No significant relationship was observed between p53 expression and caspase-3 apoptosis marker, though an association was recorded between p53 expression with DO7 and Ki-67 expression. CONCLUSIONS: In oral lichen planus, p53 protein preferentially activates the cell cycle for DNA repair, this representing a very effective genome vigilance mechanism, in view of the low rate of malignant transformations observed in this disease.

[Acute renal failure in a case of nephrotic syndrome secondary to focal and segmental glomerulosclerosis]. / Fracaso renal agudo en síndrome nefrótico secundario a glomeruloesclerosis focal y segmentaria.

Nephrotic syndrome is infrequently complicated with appearance of acute renal failure and minimal change disease is the glomerulopathy more usually involved. Pathogenesis is unclear and three possible mechanisms it has been proposed to explain the decrease of glomerular filtration rate: a severe reduction of glomerular permeability, the presence of acute tubular necrosis or an increased intrarenal pressure related with interstitial oedema. Here we present a 36 years-old-male with a nephrotic syndrome caused by focal and segmental glomerulosclerosis who developed an anuric acute renal failure. Renal function did not change despite oedema removal with haemodialysis and only after corticosteroid and cyclophosphamide therapy introduction we observed a rapid recovery of urinary output and resolution of acute renal failure. Renal biopsy did not show signs of tubular damage or obstruction with proteins nor significant interstitial oedema. Therefore, in this case we think acute renal failure was caused by a severe reduction in glomerular ultrafiltration rate and steroids were the effective treatment that allowed recovery of renal function.

Prognostic significance of p21WAF1/CIP1, p16INK4a and CD44s in tongue cancer.

The role of lost or reduced expression of p21, p16 and CD44s in the survival of tongue cancer patients was investigated. Tumours and adjacent non-tumour epithelia (ANTE) from 36 patients with tongue cancer were retrospectively studied by immunohistochemistry using monoclonal antibodies against p21, p16 and CD44s proteins. Expression of p21, p16 and CD44s and their relationship with clinical and pathological parameters were analyzed. Of 36 patients, 12 (33.33%) developed recurrence and 12 died of the disease (mean survival, 25.5 months). In four cases (11.1%), concomitant low expression (<50% of tumour cells) of p21, p16 and CD44s was detected but had no effect on survival or recurrence in the univariate analysis. In the multivariate analysis, low expression of CD44s was the sole prognostic factor related to survival (p=0.01, hazards ratio: 0.749). There was no expression of p21, p16 or CD44s in ANTE from 3 out of 24 cases studied, and this finding was related to recurrence in the univariate analysis. In the multivariate analysis, low expression of CD44s in ANTE was again the sole factor related to recurrence (p=0.002, hazards ratio: 0.028). In conclusion, low expression of CD44s is related to tumour cell invasiveness and may be of clinical relevance as a prognostic factor.

[Complete remission of nephrotic syndrome with methylprednisolone pulses in an adult with Schönlein-Henoch purpura]. / Remisión completa de síndrome nefrótico con pulsos de metil-prednisolona en un adulto con púrpura de Schönlein-Henoch.

Henoch-Schönlein purpura is a systemic vasculitis that occurs most frequently in childhood. Massive proteinuria, renal impairement at onset and histologic severity in renal biopsy are considered the main risk factors for deterioration of renal function at long-term. We report a 24 years-old woman with Henoch-Schönlein purpura who developped a severe nephrotic syndrome with microhematuria and normal renal function. Renal biopsy showed a diffuse endocapillary proliferative glomerulonephritis with less than 50% crescents (type IIIB of ISKDC classification). As their potential bad prognosis we decided to treat with methyl-prednisolone pulses (3 x 500 mg in months 0, 3 and 5) accompanied by maintenance treatment with prednisone (0,5 mg/kg/every other day) for 9 months. We observed with this protocol complete remission of nephritis with preservation of renal function.

Cell cycle regulating mechanisms in oral lichen planus: molecular bases in epithelium predisposed to malignant transformation.

OBJECTIVE: Expression of p53, p21, ki-67, Bcl-2 and caspase-3 proteins in oral lichen planus (OLP) was studied to investigate cell cycle regulation mechanisms in this disease. MATERIAL AND METHODS: Oral biopsies were obtained from 51 patients with OLP and 26 controls for immunohistochemical analysis (peroxidase antiperoxidase) to quantify expression of the proteins under study (-: 0%, +: <10%, ++: 10-25%, +++: 26-50%, ++++: >50% positive cells). RESULTS: Basal expression of caspase-3 was negative in 22 cases (46.8%) and positive in <10% of basal cells in 22 cases (46.8%); caspase-3 expression in inflammatory infiltrate was negative in 22 cases (46.8%) and positive in <10% of lymphocytes in 20 cases (42.5%). Basal expression of Bcl-2 was negative in 35 cases (74.5%); Bcl-2 was expressed in inflammatory infiltrate in 34 cases (72.3%) and was positive in <25% of lymphocytes in 14 of these (29.7%). Basal expression of p53 and p21 was positive in 32 (67.9%) and 23 (48.8%) cases, respectively. Basal expression of ki-67 was positive in 45 cases (95.7%), of which 20 (42.5%) showed positivity in >25% of cells; ki-67 was expressed in inflammatory infiltrate in 23 cases (48.9%). Significant associations were found between basal expressions of p53 and ki-67 (p<0.001) and between Bcl-2 expression in infiltrate and basal expression of ki-67 (p<0.001). No association was observed between basal expressions of p53 and caspase-3 (p=0.08). Bcl-2 expression in infiltrate and basal expression of ki-67 were independently associated with presence of OLP. CONCLUSIONS: Epithelial cells in OLP do not preferentially develop apoptosis but rather cycle arrest or an increased proliferation rate, which may create a suitable substrate for malignant transformation.

Adhesion molecule CD44 as a prognostic factor in laryngeal cancer.

BACKGROUND: Loss of expression of CD44 has been shown to be a factor of poor prognosis in some types of tumors. The purpose of this study was to analyze this event in relation to the survival of patients with laryngeal cancer. PATIENTS AND METHODS: The expression of adhesion molecule CD44 was studied in 137 patients with laryngeal cancer. Data were gathered on clinical (primary tumor location, pyriform sinus involvement and tongue base damage) and pathologic (T, N, differentiation, inflammatory response, tumor thickness, surgical margin involvement, and CD44 expression) parameters. Immunohistochemical studies were carried out using DF1485 anti-CD44 monoclonal antibody. RESULTS: In 29 tumors (21.1%) < 25%, in 18 (13.1%) 25%-49%, in 42 (30.6%) 50%-74%, and in 48 (35.0%) > or = 75% of the neoplastic cells expressed CD44. A Cox proportional risks multivariate analysis identified CD44 expression and surgical margin involvement as the parameters most associated with survival (p<0.001). CONCLUSION: The reduced expression of CD44 behaves as a marker of a poor laryngeal cancer prognosis.

[Suspicion of metastases in laryngeal carcinomas]. / Predicción de la capacidad metastásica del cáncer de laringe: implicaciones clínicas.

OBJECTIVE: To look for models predicting metastasis in laryngeal/hypopharyngeal carcinomas. DESIGN: Prospective study. PATIENTS: Sixty patients bearing laryngeal squamous cell carcinoma who were treated with curative purposes were followed prospectively with at least 10-year follow-up. PARAMETERS: Clinical (Staging, site, age, alcohol and smoking intake, surgery on the primary tumor, neck surgery) and pathological (size, number of metastatic lymph nodes, T and N staging, degree of differentiation, Jakobsson's and Glanz's scoring of malignancy, both scores in biopsies and surgical specimens) parameters were recorded in each case. METHODS: A multivariate analysis was performed to find out those parameters independently related to presence of metastases. RESULTS: The prospective study rendered tumor burden and Glanz's scoring from biopsies to be independently related with the presence of metastases. CONCLUSIONS: Malignancy grading systems must be included in laryngeal carcinoma patients' planning of neck treatment.

Granulosa cell tumor of the ovary with diffuse true hepatic differentiation simulating stromal luteinization.

A case of granulosa cell tumor of the ovary associated with hepatocytic differentiation is reported in a 45-year-old patient with a torsioned ovarian tumor. Serum alpha-fetoprotein (AFP) levels were normal 6 days postoperatively. Histopathologically, the granulosa cell tumor was typically trabecular. Its cells had nuclear grooves and were positive only for vimentin. Scattered diffusely throughout the tumor were small groups of regular polygonal cells, the cytoplasm of which secreted bile and was strongly positive for keratin, carcinoembryonic antigen (CEA), alpha-1-antitrypsin (A1AT), and ferritin and moderately positive for fibrinogen and ceruloplasmin. These results unequivocally identified them as hepatic cells. The AFP negativity of the hepatic cells was interpreted as a sign of terminal hepatocytic differentiation. The scattered arrangement of the hepatocytes simulated stromal luteinization. As neither a primary liver tumor nor any associated germ cell tumor was found, the histogenesis of the hepatic cells was thought to be metaplastic.

Myxoid leiomyosarcoma of the ovary: analysis of three cases.

The first three cases of myxoid leiomyosarcoma occurring in the ovary are reported. Two cases in stage III were found in postmenopausal patients and a further case was found in stage I in a 32-year-old. All masses were large and gelatinous with cystic change, necrosis, and hemorrhage, but both uteri and ligaments and contralateral adnexa appeared normal. Microscopically, the tumors showed a predominantly reticular meshwork of elongated cells surrounded by abundant basophilic material. While electron microscopy proved inconclusive due to nondifferentiation, the use of monoclonal antibodies against smooth muscle actin demonstrated a smooth muscle type of differentiation. The differential diagnosis of this rare ovarian condition includes other myxoid ovarian lesions, such as ovarian edema, myxoma, endodermal sinus tumors, and the sarcomatous component of malignant mixed müllerian tumor and carcinosarcoma, as well as lymphovascular tumors. Since mitotic count due to decreased cellular density is unusually low in myxoid leiomyosarcoma, capsular rupture and clinical stage seem to be more reliable prognostic markers. The highly aggressive behavior of myxoid leiomyosarcoma parallels that of typical ovarian leiomyosarcoma. Two of the three patients in this series died of tumor at 13 and 24 months after diagnosis; the other patient is free of disease at 3 years after diagnosis.

Immature endodermal teratoma of the ovary: embryologic correlations and immunohistochemistry.

Two grade 2 ovarian immature, predominantly endodermal teratomas are reported. The teratomas were in stage I and occurred in two girls, 9 and 10 years of age, who were treated with triple chemotherapy. These neoplasms differed from the usual immature ovarian teratoma as they contained no neuroectodermal components and had high alpha-fetoprotein and low human chorionic gonadotropin levels as their serum markers despite the absence of other concomitant germ cell tumors. The epithelia of the teratomas demonstrated exclusively the embryologic development of endoderm, ranging from early endoderm to tissues similar to esophagus, liver, and intestinal structures. All epithelial derivatives were positive for alpha-fetoprotein and alpha 1-antitrypsin. Liver and esophagus expressed fibrinogen, while intestine and esophagus were positive not only for carcinoembryonic antigen and chromogranins but also for thyroglobulin, thus reflecting yet another type of endodermal differentiation into thyroid. Focal human chorionic gonadotropin positivity associated with primitive intestinal and esophageal epithelia may reflect the early embryologic relationships between endoderm and trophoblast. These cases demonstrate that simultaneous alpha-fetoprotein and human chorionic gonadotropin secretion may occur in immature teratoma. The mesenchymal component also showed a wide range of differentiation, from primitive mesoblastic cells to differentiated cells, such as hemopoietic foci, smooth muscle, bone, and cartilage. Both the primitive endoderm and the mesenchyme co-expressed vimentin and keratin, reflecting their intimate developmental relationships and possibly supporting the hypothesis of mesenchyme originating from endoderm, as suggested by previous embryologic studies. Since endodermal and mesenchymal areas similar to those described here are found in association with yolk sac tumors and embryonal carcinoma, it is possible that the present cases may represent an endodermal differentiation accomplished by either of these developmentally related germ cell tumors.

P21WAF1/CIP1 protein and tongue cancer prognosis.

The expression of the cell cycle regulatory protein p21waf1/cip1 was analyzed immunohistochemically in tissue from the tumor and adjacent non-tumor epithelia of 54 patients with tongue cancer in order to determine the proportion of tongue carcinomas with altered p21waf1/cip1 expression, establish whether this alteration is an early event in tongue carcinogenesis and to investigate whether p21waf1/cip1 expression has predictive prognostic value in these tumors. The percentage of p21waf1/cip1-positive neoplastic cells was calculated. Adjacent non-tumor epithelium was classified as normal, hyperplastic or dysplastic, and the p21waf1/cip1 expression was only considered normal in suprabasal layers. P21waf1/cip1 expression was negative in 57.4% (31/54) of the tumors and was aberrant in the non-tumor adjacent tissue of all patients studied. Neither the absence nor the degree of p21waf1/cip1 expression influenced the survival of patients in the present series. P21waf1/cip1 system alteration may be an early and frequent event in tongue carcinogenesis.