Nuclear DNA content, proliferating-cell nuclear antigen (PCNA) and p53 immunostaining in predicting progression of laryngeal cancer in situ lesions

Biomarkers of laryngeal squamous cell carcinoma: a review

Laryngeal carcinoma is the second common malignancy of the upper aerodigestive tract after lung cancer; in most cases is a squamous cell carcinoma, whose risk factors include tobacco smoking and alcohol consumption. Despite therapeutic progress, the five-year overall survival rate for this malignancy has remained nearly 50% and many patients already present metastasis at the time of diagnosis. To date, there are no tools that predict the evolution of laryngeal carcinoma: in this light, during the last years, many studies were planned with the aim to investigate the role played by different biomarkers expressed by larynx cancer, which can help make an early diagnosis, predict disease evolution and direct therapeutic choice. This review aims to summarize these markers and correlating them with disease evolution.

Myosin light chain kinase is a potential target for hypopharyngeal cancer treatment

Hypopharyngeal cancer is squamous cell carcinoma (SCC) with the worst prognosis among the head and neck cancers. Overall, the 5-year survival rate remains poor although diagnostic imaging, radiation, chemotherapy, and surgical techniques have been improved. The mortality of patients with hypopharyngeal cancer is partly due to an increased likelihood of developing a second primary malignancy and metastasis. In this study, we found that MLCK expression, compared to healthy tissue, was up-regulated in hypopharyngeal tumor tissue. Of particular interest, a low 5-year survival rate was positively correlated with MLCK expression. We hypothesized that MLCK might be a target for hypopharyngeal cancer prognosis and treatment. In order to explore the function of MLCK in the development of cancer, we knockdown MLCK in hypopharyngeal cancer FaDu cells. The results showed that MLCK knockdown reduced the migration and invasion of FaDu cells. 4-amino-2-trifluoromethyl-phenyl retinate (ATPR) is the derivative of all-trans retinoic acid (ATRA), which was able to reduce both MLCK expression and activity in FaDu cells. ATPR induced FaDu cells apoptosis in a dose-dependent manner and also inhibited cell growth both in vivo and in vitro. Further experiments showed that overexpression of MLCK reduced ATPR induced-migration inhibition while increase of ATPR induced apoptosis, which suggested that MLCK was involved in ATPR's anti-cancer function. In conclusion, MLCK is a novel prognostic marker and therapeutic target for hypopharyngeal cancer. By targeting MLCK, ATPR exhibits its potential application in the treatment of this type of cancer.

The role of E-cadherin and β-catenin in laryngeal cancer

Epithelial cadherins with catenins form the E-cadherin-catenin complex that acts on cell-to-cell adhesion. The loss of these complex lead to the reduction or absence of epithelial cadherin expression in the cell membrane, cytoplasmic accumulation of β-catenin and its translocation to the nucleus, contributing to carcinogenic events. The objective of this study was to evaluate the expression of epithelial cadherin and β-catenin in patients with laryngeal tumor. A retrospective study of 52 patients with glottic or supraglottic squamous cell carcinoma was conducted and evaluated according to the tumor site, histological differentiation, TNM stage, survival analysis and compared with the immunohistochemical expression of epithelial cadherin and β-catenin. We observed statistically significant association between the epithelial cadherin expression reduction and supraglottic localization of the lesion, the presence of cervical metastasis, poorly differentiated tumors and locally advanced tumors when in glottic topography. Related to the expression of β-catenin, statistical significance was also found to the presence of cervical metastasis and tumor of low differentiation with the decreased expression of this marker. Regarding survival analysis, the low expression of β-catenin is related to worse overall survival and the reduction of expression of both markers to worse disease-free survival. We concluded that the reduction in expression of the markers studied leads to a prognostic impact as they are related to tumors with greater local aggressiveness and presence of cervical metastasis.

Lead article: The prognostic significance of proliferating cell nuclear antigen (pcna) in laryngeal cancer

Squamous cell carcinoma arising from upper aerodigestive tract carries with it a significant morbidity and mortality and, over the last few decades, its incidence has steadily increased. The management of patients requires thorough investigation to determine the local, regional, and distant extent of the disease, and treatment options include surgery, radiotherapy, chemotherapy, or combinations of these.Despite the large number of therapeutic and hsitopathologic studies in print, there is currently no morphologic or cytologic feature available which consistenly predicts outcome in patients with laryngeal carcinoma. The use of proliferating cell nuclear antigen (PCNA), a newly available marker of a cell's proliferative activity ( S-phase fraction), was evaluated in 25 cases of squamous cell carcinoma of the larynx. PCNA scores differed, statistically significantly as far as the localization of the lesion, pathological grade, clinical stage, presence of lymph node metastases and prognosis of the patients were concerned.These data suggest that PCNA is an indicator of the malignant potential of the larynx. PCNA can be used in decision making for treatment and assessing prognosis in carcinoma of the larynx.

Cell kinetics and apoptosis in laryngeal carcinoma patients

Cellular proliferation and apoptosis are both implicated in the process of carcinogenesis. The objective of this study was to access the prognostic significance of the expression of proliferating cell nuclear antigen (PCNA) and the apoptosis-related genes (bax, bcl-2, and p53) in laryngeal carcinoma patients. Thirty consecutive patients with stage I to IV squamous cell laryngeal carcinoma were treated in our department from 1992 to 1994. We immunohistochemically studied the expression of PCNA and bax, bcl-2, and p53 genes in their tumor specimens. Five healthy men were used as the control group. The staining results were correlated with clinicopathologic data. The PCNA protein expression was correlated with a significantly worse survival in those patients who were bax-negative (0% versus 42.86%, p = .0445). Similarly, the presence of PCNA led to an unfavorable clinical outcome in those patients who were bax-negative, bcl-2-negative, and p53-negative (0% versus 50%, p = .0278). Expression of bcl-2 protein was found to be an independent prognostic factor related to an unfavorable clinical outcome (p = .0262). The expression of bcl-2 protein appears to predict survival in laryngeal carcinoma patients. Furthermore, the combined study of proliferation markers and apoptosis-related genes helped us to identify a high-risk group of patients who may benefit from a more aggressive treatment protocol.

Gradual deregulation and loss of PCPH expression in the progression of human laryngeal neoplasia

PCPH is a gene involved in the regulation of eukaryotic cell proliferation and stress response. Recently, analyses of human and animal solid tumors and cell lines suggested that PCPH protein deregulation may participate in neoplastic progression. To test this possibility, we first examined PCPH expression in several laryngeal carcinoma cell lines by Western analysis. The results showed the presence of altered PCPH polypeptides in these cells, accompanied by the loss of the PCPH form present in normal laryngeal epithelial cells, a deregulated expression pattern similar to that reported previously. We then analyzed PCPH expression in 59 dysplastic lesions of the human larynx, representative of the mild, moderate, and severe stages of the disease. Immunohistochemical data showed that, compared with normal laryngeal mucosa, PCPH expression in the dysplastic samples was associated with areas of epithelial cell maturation rather than with regions of increased proliferation. Furthermore, PCPH expression decreased parallel to the increase in cellular atypia of the dysplastic samples: PCPH either was expressed at very low levels or not expressed in cases of severe dysplasia/carcinoma in situ. This trend toward loss of PCPH expression along malignant progression of the larynx was confirmed by the low to null expression of PCPH in samples of invasive laryngeal carcinoma and by the complete absence of PCPH immunostaining in a laryngeal carcinoma-derived liver metastasis. These results indicated that PCPH protein analysis might allow for the distinction between grades of laryngeal dysplasia. In addition, detection of altered PCPH polypeptides by Western analysis potentially can be applied to the early identification of laryngeal squamous cell carcinoma.

Proliferative (MIB1, mdm2) Versus Anti-Proliferative (p53) Markers in Head and Neck Cancer. An Immunohistochemical Study

Formalin fixed and paraffin embedded samples from 36 squamous cell carcinomas of the larynx and the oral cavity (pT2N0M0, R0) surrounded by non-tumorous mucosa were studied immunohistochemically using a panel of four different anti-p53 antibodies (CM1, PAb1801, D07, PAb240), a monoclonal anti-mdm2 antibody and MIB1, following wet autoclave antigen retrieval. P53 immunoreactivity was detected in 11/14 laryngeal and in 9/22 oral carcinomas. All p53 positive oral, and all but one laryngeal tumors revealed mdm2 positivity as well, whereas in p53 negative tumors 4/12 and 1/3 mdm2 immunopositive cases were demonstrated, respectively. MIB1 labeling indices of the tumors ranged between 18% - 64% in p53 positive cases, and 10% - 53% in p53 negative ones. The difference was not statistically significant. Close spatial coexpression of p53, mdm2 and MIB1 immunoreactivity was observed at the invasive front of the carcinomas and in the basal and suprabasal layers of the non-tumorous epithelium in all p53 positive cases. However, the MIB1 expression was similarly increased at the invasive margins in carcinomas lacking immunohistochemically detectable p53 alterations. Our results strongly suggest that p53 overexpression does not necessarily correspond to increased rate of proliferation, but rather to mdm2 overexpression and is largely dependent on the anatomical site in case of small and localized squamous cell carcinomas of the head and neck region.

Retinoblastoma gene product and P21 (WAF1, CIP1) protein expression in non Hodgkin's lymphomas: a multivariate survival analysis

We evaluated immunohistochemically the expression of two negative regulators of the cell cycle, namely retinoblastoma gene product (pRb) and WAF1/Cip1 gene product (p21), in paraffin sections from 93 patients with non-Hodgkin's lymphomas (NHL) and related it to clinicopathological parameters, proliferative fraction, p53 expression and survival. Patients were followed until death (n=33) or for an average of 52 months (60-160). Rb labelling index (LI) increased with malignancy grade and proliferative activity but was unrelated to other clinicopathological parameters. In 33% of cases, especially those of the aggressive groups, we observed diminished pRb expression (i.e. low pRb/Ki-67 ratio). p21 expression on the other hand correlated only with histological grade, Rb LI and p53 LI. In multivariate analysis, Rb LI was a negative predictor of disease-free survival but was linked to a higher probability of complete response. However, diminished pRb expression as well as p21 expression were not statistically significant prognostic indicators. Our results suggest that pRb as a cell cycle related molecule may play an important role in determining prognosis and therapeutic response in NHL patients.

Immunohistochemically stained markers (p53, PCNA, bcl-2) in dysplastic lesions of the larynx

The percentage of malignant transformation of laryngeal dysplastic lesions is difficult to estimate. There is a need for new histological markers which could enable more objective assessment of the premalignant stages of the larynx and help in estimation of the potential of future neoplastic progression. We performed a retrospective study to determine whether immunohistochemical staining for the proliferating cell nuclear antigen (PCNA), tumour suppressor gene protein p53 and antiapoptotic protein bcl-2 may be prognostic factors in laryngeal epithelial lesions. Staining was performed on 57 paraffin-embedded biopsies from patients with clinically detected precancerous stages of the larynx. Histopathologic examination revealed normal epithelium in six cases, mild dysplasia in 20 cases, moderate dysplasia in 18 cases, severe dysplasia in seven cases, CA in situ in four cases, papilloma in one case and CA invasivum in one case. The p53 count in mild and moderate dysplasia was 26.8 and 38.6%, respectively. This difference was statistically significant. There was significant correlation between PCNA and p53 scores. There was also a relationship between the scores of these markers and bcl-2 expression. In ten out of 45 cases of dysplastic lesions the invasive cancer developed in 4 years of follow-up. The correlation between PCNA score and malignant progression of the dysplastic lesions was on the statistical borderline. There was significant relationship between malignant transformation and age of the patients.

Immunoreactivity in granular cell tumours of the larynx

OBJECTIVE

To elucidate histogenesis and behaviour of laryngeal granular cell tumours (GCT) and to determine the role of p53 protein expression in these lesions.

METHODS

The clinical, pathological and immunohistochemical findings of three cases of laryngeal GCTs are described.

RESULTS

All tumours were surgically excised and appeared histologically benign. Pseudoepitheliomatous hyperplasia, mitosis and nuclear pleomorphism were not found in any of the three cases. All lesions were negative for keratin 8, desmin and actin. Only one case stained for collagen IV. Positive staining was found for S-100 protein and CD68 in all tumours. Ki-67 and Bcl-2 staining was confined to occasional cells. p53 reactivity was seen in all tumours; positivity ranged from 35 to 42%. The three patients have remained free of disease without complications up to 10 years after treatment.

CONCLUSION

Immunohistochemical findings support benign behaviour and a Schwann cell origin for laryngeal GCT. The expression of p53 by granular cells is unclear but appears to be unrelated to behaviour.

Prognostic relevance of apoptotic cell death in non-Hodgkin's lymphomas: a multivariate survival analysis including Ki67 and p53 oncoprotein expression

AIMS

To evaluate the independent prognostic value of apoptotic versus proliferative fractions in a series of 92 patients with non-Hodgkin's lymphomas (NHL).

METHODS AND RESULTS

Apoptotic fractions were quantified by use of the TdT (terminal deoxynucleotidyl-transferase)-mediated in-situ end-labelling technique (TUNEL), the percentage of positive cells constituting the apoptotic index (AI). Proliferative rate was expressed as percentage of Ki67 positive cells (Ki67 LI). Tissues were also stained for p53 protein with the DO-1 antibody. Patients were followed up until death (n = 33) or for an average of 63 months (n = 56). AI increased with malignancy grade and proliferative activity but was not related to location, cell of origin, clinical stage, bone marrow involvement and p53 expression. In multivariate analysis, overall survival was independently influenced by grade, stage, p53 LI and chemotherapy. The independent predictors of disease-free survival were Ki67 LI location and chemotherapy. AI turned out to be the only independent (negative) predictor of post-relapse survival. On the other hand, a low Ki67 LI increased the risk of relapse (logistic regression analysis) whereas a low p53 LI increased the probability of complete response.

CONCLUSIONS

Our results suggest that the combined assessment of apoptotic fraction, proliferative rate and p53 expression may provide important prognostic information independent of other clinicopathological parameters in NHL.

Prognostic implications of proliferating cell nuclear antigen (PCNA), AgNORs and P53 in non-Hodgkin's lymphomas

We investigated the prognostic value of proliferating cell nuclear antigen (PCNA) and p53 oncoprotein expression and of nucleolar organiser region (NOR) scoring, in relation to classic clinicopathological parameters, in a series of non-Hodgkin's lymphomas (NHL). Paraffin embedded tissue from 91 patients with NHL was stained immunohistochemically with the monoclonal antibodies PC-10 (PCNA) and DO-1 (p53) and histochemically with the AgNOR technique. The median follow-up was 48 (4 to 193) months. The impact of PCNA and p53 expression and of AgNOR number on survival was tested using univariate as well as multivariate analysis, in order to circumvent the heterogeneity in histologic grade, type and therapy. Univariate analysis identified seven variables related to overall survival: histologic type and grade, clinical stage, chemotherapy, p53 labelling index (LI), PCNA LI and AgNOR score, whereas only one parameter i.e. histologic grade influenced disease-free survival. In multivariate analysis stage, PCNA LI and AgNOR score predicted independently overall survival. PCNA was also the only independent predictor of post-relapse survival and histologic grade the most important indicator of disease-free survival. In conclusion, PCNA expression and AgNOR number may be better predictors of overall and post-relapse survival than histologic grade. The latter remains the most valuable prognostic indicator of disease-free survival.

p53 expression in oral precancer as a marker for malignant potential

The potential of p53 protein expression as a marker for determining which oral precancerous lesions may transform to malignancy with time was assessed. We compared the p53 expression in archival formalin-fixed, paraffin-embedded tissues from 22 baseline biopsies of precancerous lesions that transformed to cancer in 4-25 years against that in 68 similar lesions that did not transform over the same time period. Twenty-nine percent of precancers that transformed were p53-positive at baseline, compared to 31% of the biopsies that did not transform to malignancy. When examined by immunohistochemical methods p53 expression failed to detect potential malignant status of oral precancer. Non-specificity of the assay may account for this result but overexpression of p53 due to DNA damage by tobacco/betel-quid in non-progressive lesions needs further study. Nine precancerous lesions became p53-immunoreactive from precancer to cancer. This may suggest p53 overexpression peaks close to the time of transition from precancer to cancer rather than early in the natural history of oral precancer.

The role of p53, MDM2 and c-erb B-2 oncoproteins, epidermal growth factor receptor and proliferation markers in the prognosis of urinary bladder cancer

The immunohistological expression of p53 and MDM2 oncoproteins was examined in paraffin embedded tissue from 106 patients with transitional cell carcinoma of the urinary bladder and was related to various clinicopathological features, the expression of proliferation associated markers (proliferating cell nuclear antigen - PCNA - and Ki-67), c-erb B-2 oncoprotein and epidermal growth factor receptor (EGFR), as well as to survival. MDM2 immunoreactivity was seen in 38% of our cases, and in 14% was accompanied by p53 positive immunohistochemistry. The rate of p53 positivity was associated with grade, stage and papillary status, whereas MDM2 immunopositivity increased with grade and stage (Ta VS T1), and MDM2 labeling index (LI) with stage. MDM2 expression was related to p53 expression and less strongly to proliferation rate (Ki-67 LI). The simultaneous p53 and MDM2 expression was more frequently observed in higher grade and stage tumours. C-erb B-2, EGFR and proliferation marker expression increased with grade, stage and non-papillary configuration. In univariate analysis high grade, solid growth pattern, advanced T-category, cystectomy, EGFR and Ki-67 expression were linked to shorter overall survival but only Ki-67 LI, along with T-category and type of therapy, had independent prognostic value. C-erb B-2 expression and stage were the two independent predictors of disease-free survival and Ki-67 LI and EGFR LI the independent predictors of post-relapse survival. For patients with superficial tumors PCNA LI emerged as the single independent determinator of survival. p53 and MDM2 expression did not appear to have any significant impact on survival, although the simultaneous expression of p53 and MDM2 turned out to be a highly significant parameter of shortened overall survival in univariate analysis.

Proliferating cell nuclear antigen in laryngeal cancer

The expression of proliferating cell nuclear antigen in paraffin sections from 154 cases of laryngeal squamous cell carcinoma were examined. There was significant difference in PCNA expression between the control group and cancer patients (p < 0.001). The mean score of PCNA was higher in patients with poor prognosis than in patients with satisfactory outcome after treatment (p < 0.05). There was no significant correlation between the PCNA count and the patient's age and sex, T and N stage and site of the tumour. Univariate analysis revealed that the PCNA score correlated with the patients' survival rates. In multivariate analysis the prognostic value of PCNA was on the statistical borderline (p = 0.049). In our study clinical features like N and T status had a more important influence on survival rate. Nevertheless it appears that the immunohistological examination of PCNA in paraffin section could be a complementary prognostic tool for laryngeal carcinoma. PCNA expression may also be a valuable tool for differentiating malignant from benign laryngeal epithelium.

p53 immunostaining and image cytometry DNA analysis in precancerous and cancerous squamous epithelial lesions of the larynx

BACKGROUND

Squamous epithelial cancer can develop from progressive epithelial changes connoted dysplasias. Histopathologic evaluation/grading of these lesions is difficult and gives poor information concerning the risk for progression to cancer. Squamous cell carcinoma of the head and neck (SCCHN) frequently show p53 alteration and DNA-ploidy aberration. Could these markers be used as indicators for malignancy risk in the larynx?

METHODS

Immunohistochemical staining (IHC), with the CM-1 antibody against p53, and image cytometry (ICM) DNA analysis were performed in 60 lesions from 12 patients--and 21 controls--who were initially seen with laryngeal lesions prior to cancer in situ (cis) or invasive cancer diagnosis at the same site.

RESULTS

All but one of the invasive cancers, and 77% of the lesions which preceded cancer or cancer in situ, showed positive p53 immunostaining, as compared with only 10% of the controls. All but one of the invasive cancer lesions, and 77% of the precancerous lesions, showed aberrant DNA-ploidy results, whereas all controls were diploid. When DNA and p53 analysis were combined, only one of the lesions preceding cis or invasive cancer was negative.

CONCLUSIONS

Both p53 immunoreactivity and DNA-ploidy aberration appear to be early events in the multistep process of squamous epithelial carcinogenesis. Immunohistochemical staining p53 analysis and ICM DNA analysis does increase the diagnostic sensitivity for cancerous and true precancerous lesions in the larynx.

Epidermal growth factor receptor, c-erbB-2 and p53 overexpressions in epithelial hyperplastic lesions of the larynx

An immunohistochemical analysis of overexpression of epidermal growth factor receptor (EGFR), c-erbB-2, and p53 proteins was performed on 43 biopsies of laryngeal epithelial hyperplastic lesions (EHLL), classified according to the Kambic-Lenart classification, and in 11 cases of laryngeal carcinoma (SCCL). The aim of the present study was to determine whether there is a correlation between the staining patterns of these proteins and different grades of EHLL, and to reveal their possible prognostic value. We compared the staining patterns of atypical hyperplasia adjacent to cancer with the same type of lesions which have not turned malignant. p53 and EGFR overexpressions were detected in 28/54 (52%) and 33/54 cases (61%), respectively, and tend to increase with the degree of epithelial changes. The intensity of staining in various grades of EHLL adjacent to cancer was more pronounced than the same type of lesions which have not progressed to cancer. c-erbB-2 was weakly positive in the majority of cases, and changed from predominantly membranous in simple hyperplasia to cytoplasmic staining in abnormal and atypical hyperplasias. There was no significant statistic correlation between the amount of positive cells for all proteins and the grade of epithelial abnormalities. We conclude that the overexpression of each biomarker itself adds little predictive value over routine histomorphology, and cannot be regarded as a reliable prognostic factor for EHLL. However, the histologic characteristics of atypical hyperplasia together with the immunostaining patterns of EGFR and p53 up to two-thirds or more of the epithelial thickness could be considered a reliable pattern which correlates with the progression to cancer.

Potential biomarkers in predicting progression of epithelial hyperplastic lesions of the larynx

Factors contributing to malignant transformation of laryngeal pre-neoplastic lesions remain largely unknown. Potential etiologic factors may be related to a genetically controlled sensitivity to environmental carcinogens. In this study, we investigated bleomycin-induced chromosome fragility in 15 patients with laryngeal keratoses who experienced a malignant transformation of pre-neoplastic lesions during follow-up, as compared with chromosome fragility in 15 historical controls with no progression of laryngeal keratoses during a 10-year follow-up, in a match-paired analysis. Chromosomal analysis demonstrated a higher sensitivity to clastogens in patients with malignant progression of laryngeal pre-neoplastic lesions than that of control patients with no evolution of their original laryngeal keratoses (p < 0.01). Furthermore, in the attempt to identify possible prognostic markers we studied proliferative activity (MIB-1 expression) and p53 gene aberration in biopsy samples from non-invasive and invasive laryngeal lesions in both groups. p53 immunostaining was observed in 10/15 (66.7%) of pre-neoplastic lesions and in 11/15 (73.3%) of metachronous laryngeal cancers. No differences in terms of p53 expression were noted between transformed and not-transformed lesions. Mutations at p53 gene were observed in 3/15 (20%) of pre-invasive biopsies and in 4/5 (80%) of the laryngeal cancers analyzed. Our data suggest that p53 alteration is an early event in the genesis of a subset of laryngeal carcinomas and that there is no conclusive data about the possible clonal development of metachronous laryngeal carcinoma from a p53 mutated pre-invasive disease in the same patient. MIB-1 expression was found to progressively increase with degree of epithelial hyperplasia and dysplasia in both transformed (p = 0.007) and not-transformed (p < 0.1) lesions. Surprisingly, pre-invasive lesions with tumor evolution showed a lower proliferative activity when compared with laryngeal lesions without malignant transformation (p = 0.013). These data suggests that subjects with pre-neoplastic laryngeal lesion showing an increased susceptibility to carcinogens and with less proliferative disease could be at a higher risk for development of laryngeal carcinoma.

Increased mutagen-induced chromosome damage in patients with transformed laryngeal pre-cancerosis

Factors that contribute to malignant transformation of laryngeal pre-neoplastic lesions remain largely unknown. Potential etiological factors may be related to a genetically controlled sensitivity to environmental carcinogens. In this study, we investigated bleomycin-induced chromosome damage in 15 patients who experienced a malignant transformation of preneoplastic laryngeal lesions during follow-up, as compared with chromosome fragility in 30 historical controls with no progression of keratoses during a 10-year follow-up, in a match-paired analysis. Chromosomal analysis demonstrated higher sensitivity to clastogens in patients with malignant progression of laryngeal pre-neoplastic lesions than that of control patients with no evolution of their original laryngeal keratoses (p = 0.003). Furthermore, among the study patients, chromosome sensitivity was most apparent in non-tobacco users with malignant transformation of laryngeal disease. Our data suggest that subjects with pre-neoplastic laryngeal lesion showing increased susceptibility to carcinogens could be at higher risk for development of laryngeal carcinoma.

Epidemiology of laryngeal cancer

Laryngeal cancer is the second most common respiratory cancer after lung cancer. Its incidence is increasing over time in much of the world and this increase is generally accepted to be related to changes in tobacco and alcohol consumption. It is a relatively common cancer in men, but rarer in women. Moreover, interesting new issues have been raised recently about the influence of other possible risk factors. Evidence from epidemiological studies which supports the involvement of new risk factors in the aetiology of larynx cancer, as well as new perspectives in therapy, must be taken into consideration in order to realise primary and tertiary prevention. However, it remains clear that, even as new evidence continues to amass about a wide range of risk factors, primary prevention of the great majority of laryngeal cancers could be achieved by elimination of tobacco smoking and reduction of consumption of alcoholic beverages. With an additional contribution from adoption of a diet rich in fruits and vegetables, the great majority of laryngeal cancer appears to be preventable within our current epidemiological knowledge.

Laboratory probing of oncogenes from human liquid and solid specimens as markers of exposure to toxicants

Recent discoveries regarding the mechanistic role of oncogenes and tumor suppressor genes in cancer development have opened a new era of molecular diagnosis. It has been observed repeatedly that genetic lesions serve as tumor markers in a broad variety of human cancers. The ras gene family, consisting of three related genes, H-ras, K-ras, and N-ras, acquires transforming activity through amplification or mutation in many tissues. If not all, then most types of human malignancies have been found to contain an altered ras gene. Because the ras oncogenes actively participate in both early and intermediate stages of cancer, several highly specific and sensitive approaches have been introduced to detect these genetic alterations as biomarkers of exposure to carcinogens. There is also mounting evidence that implicate chemical-specific alterations of the p53 tumor suppressor gene detected in most human tumors. Therefore, it seems a reliable laboratory approach to identify both altered p53 and ras genes as biomarkers of human chronic or intermittent exposure to toxicants in a variety of occupational settings.

Expression of Ki-67 antigen and proliferative cell nuclear antigen in benign and malignant epithelial lesions of the larynx

In an attempt to analyse the proliferative activity in benign and malignant laryngeal epithelial lesions, and to determine the relationship to their histologic grade, we studied the expression of proliferative cell nuclear antigen (PCNA) and Ki-67 antigen on 20 squamous carcinomas, and on 30 biopsies of epithelial hyperplasia categorized according to the Kambic-Lenart classification into simple, abnormal, and atypical hyperplasias. In simple hyperplasia, both antibodies stained the nuclei of the occasional cells in the basal layer. In abnormal hyperplasia (mild dyplasia), positive cells occupied up to a third, and in atypical hyperplasia (moderate and severe dysplasia) they occupied from two-thirds to the entire epithelial thickness. In squamous carcinoma, we have found a statistically significant correlation between its grade and the percentage of Ki-67-(p < 0.01) and PCNA-(p < 0.00001) positive cells. Our results suggest that the proliferative fraction progressively increases with the degree of epithelial hyperplasia and the grade of carcinoma. We conclude that the patterns of immunoreactivity to PCNA and Ki-67 antigen correspond to the histologic grade of both benign and malignant epithelial lesions of the larynx. This method should be regarded as a useful adjunct to traditional histological techniques allowing more objective grading of benign and malignant epithelial lesions.

Expression of proliferating cell nuclear antigen in premalignant lesions of the larynx

PURPOSE

This study was performed to 1) evaluate the proliferative activity in premalignancies of the larynx by immunostaining for proliferating cell nuclear antigen (PCNA), 2) to examine the relationship between PCNA expression and histological diagnosis and 3) to evaluate clinical values of PCNA immunostaining.

MATERIALS AND METHODS

The percentage of PCNA-positive nuclei (PCNA index) and their highest location (PCNA grade) were evaluated in 44 specimens of premalignant lesions, 7 premalignant lesions near carcinomas, 9 normal epithelium, and 12 early invasive carcinomas of the larynx. Follow-up was conducted.

RESULTS

The mean of PCNA indices in premalignancies was significantly higher than in normal epithelium but lower than in early invasive carcinomas. PCNA index had no apparent correlation with the histological diagnosis, but in the same case, the higher degree of dysplasia showed higher PCNA index. PCNA grade showed significant correlation with the histological diagnosis. Cases with higher PCNA expression showed higher percentages of recurrence and cancerization. Premalignant lesions near carcinomas presented significantly high PCNA expression.

CONCLUSIONS

The proliferative activity in premalignancies of the larynx is higher than in normal epithelium and lower than in carcinomas. It differs from case to case, but in the same case the higher degree of dysplasia possesses higher proliferative activity. Dysplasia is associated with abnormal proliferation pattern. Special attention should be paid to those with abnormal proliferation patterns as well as high proliferative activity. PCNA immunostaining is of some referential value in predicting clinical outcome and guiding to make an early diagnosis of malignancy.

Expression of proliferating cell nuclear antigen (PCNA) and Ki-67 in soft tissue sarcoma. Is prognostic significance histotype-specific?

Abnormal patterns of proliferation characterize the behavior of many tumors. Proliferating cell nuclear antigen (PCNA) and Ki-67 are two cell cycle antigens which are expressed in proliferative states. Our study examines the prognostic value of these cell-cycle antigens in soft tissue sarcoma (STS). Paraffin-embedded primary tumor tissues from 185 patients (1980-92) were stained with the anti-PCNA antibody PC-10; 182 of these were stained with the antibody MIB-1 for Ki-67. Using PCNA (< or = 50; > 50%) and Ki-67 (< or = 10; > 10%) indices, we examined and compared metastasis-free survival (MFS) in a mixed-histotype group, as well as after subdivision into MFH and non-MFH groups. Fifty-seven patients developed metastases. The median follow-up for survivors was 6 (2-13) years. In the mixed series, the 2-year MFS for a PCNA index < or = 50 was 76%, and for an index > 50 56%. Survival predicted by Ki-67 index was comparable. PCNA index (but not Ki-67) strongly correlated with the incidence of metastasis in MFH tumors and predicted 2-year MFS of 81 vs 48%. In contrast, Ki-67 index (but not PCNA) strongly correlated with metastasis in non-MFH tumors and predicted 2-year MFS survival of 90 vs 45%. No correlation existed between PCNA and Ki-67 indices in the mixed histotype, MFH or non-MFH groups. In combination, a high PCNA and Ki-67 index correlated with poor survival, a high PCNA and lower Ki-67 index (or vice versa) with an intermediate survival, and low PCNA and Ki-67 indices with the best survival. The pattern of PCNA and Ki-67 expression raises the possibility of histotype specificity.

Immunohistochemical detection of p53 protein in preneoplastic lesions and squamous cell carcinoma of the head and neck

Alterations in the p53 tumor suppressor gene are the most frequent genetic abnormalities in human cancers. The p53 protein is present in normal cells, and is assumed to induce G1 arrest or apoptosis in the presence of DNA lesion. The mutant protein lacks this property. Squamous cell carcinomas of the head and neck (SCCHN) are related to carcinogens in tobacco and alcohol, and provide a good model of multiple-step carcinogenesis in association with DNA damage and p53-related tumorigenesis. Stabilization of the mutant p53 protein allows immunohistochemical analyses (IHC) to be routinely used to demonstrate the mutant p53 protein in tissue samples, whereas normal p53 protein is undetectable. Ninety-nine squamous cell carcinomas, 8 in situ carcinomas, 31 preneoplastic lesions and 79 normal carcinogen-exposed mucosas of the head and neck from a total of 107 patients were examined for the expression of p53 tumor suppressor gene protein. Samples were collected before treatment, and stained with p53 specific mono- and polyclonal antibodies (DO-7, Pab 1801 and 240, CM1) using an indirect immunoperoxidase technique. Proliferating cell nuclear antigen (PCNA) provided semiquantitative estimates of proliferation. The main localizations were the pharynx (64/107) and the larynx (21/107). Positive IHC detection of p53 was observed in 9% of normal-appearing carcinogen-exposed mucosas, 37% of hyperplasias, 68% of dysplasias, 75% of in situ carcinomas, and 56/99 (56.5%) of primary tumor samples. Mucosas from 15 control patients under 10 years of age were negative. There was no correlation between p53 IHC and localization, differentiation or TNM staging.(ABSTRACT TRUNCATED AT 250 WORDS)

High prevalence of p53 protein overexpression in patients with esophageal cancer in Linxian, China and its relationship to progression and prognosis

BACKGROUND

Linxian is the highest endemic area of esophageal squamous cell carcinoma (ESCC) in China and one of the highest incidence areas in the world. The relationship of p53 protein accumulation to geographic variation, pathologic findings, and prognosis has not been investigated extensively.

METHODS

Formalin fixed, paraffin embedded ESCC tissues from 100 patients who underwent esophagectomy between 1973 and 1983 were immunostained by using monoclonal antibody pAB1801.

RESULTS

p53 overexpression was observed in 41 (87.2%) of 47 tumors of patients in Linxian and in 16 (64%) of 25 additional patients outside Linxian. Its prevalence in the noncancerous epithelium (11/72, 15.3%) and carcinoma in situ (1/7, 14.3%) was lower than that in invasive lesions (64/93, 68.8%). Its immunostaining intensity increased with the depth of cancer invasion. Of 30 primary carcinomas with lymph node metastasis, 29 (96.7%) were positive. However, only 36 (51.4%) of 70 primary lesions without metastasis were positive, and a higher intensity was noticed in the metastases. There was a lower expression rate in tumors of patients surviving more than 10 years (25/52, 48.1%) than in those surviving less than 3 years (40/48, 83.3%). Overall and nonadvanced or metastasis-free cumulative survival rates were both significantly different in patients with and without p53 protein overexpression.

CONCLUSIONS

There is a higher expression rate of p53 protein in ESCC in tumors of patients from Linxian than in those from the surrounding area. The accumulation of p53 protein is related to the invasiveness and capability for metastases of cancer cells and appears to be a useful prognostic factor for patients with ESCC.