DNA content in reactive hyperplasia, precancerosis, and carcinomas of the oral cavity. A cytophotometric study

Exfoliative cytology for diagnosing oral cancer

Exfoliative cytology is a minimally invasive technique for obtaining oral cell specimens from patients for diagnostic purposes. Classical applications of oral cytology studies, such as oral candidiasis, have been extended to include oral precancerous and cancerous lesions. A number of analytical methods are available for studying cytology specimens. The development of molecular analysis techniques, the oral cancer etiopathogenic process, and improvements in liquid-based exfoliative cytology are leading to renewed interest in exfoliative cytology. Results sometimes are disputed, so the aim of our review was to clarify the applicability of exfoliative cytology to the diagnosis of oral precancerous and cancerous lesions.

Pseudoaneuploid subpopulations detected in normal upper aerodigestive tract mucosa consistent with physiological apoptosis in normally differentiating squamous mucosa

OBJECTIVES

While evaluating the validity of using normal human mucosal cells from the upper aerodigestive tract as diploid standards for DNA content studies of squamous cell cancer of head and neck by flow cytometry, pseudoaneuploidy was frequently detected. The purpose of this study was to further evaluate these DNA content abnormalities encountered in normal human mucosal cells and correlate them to physiological apoptosis.

STUDY DESIGN

Thirty-two specimens of upper areodigestive tract mucosa from 18 surgical resections, 11 fresh autopsies, and 3 buccal scrapings were examined for DNA content by flow cytometry.

RESULTS

Pseudoaneuploidy, which ranged from sub-G0/G1 peaks to hyperdiploid peaks with increased 90 degrees light scattering properties was found in 60% of these specimens. Fluorescent microscopic examination of the sorted DNA pseudoaneuploid cells demonstrated cells undergoing apoptosis.

CONCLUSION

This unexpected pseudoaneuploidy in normal mucosal cells was a result of physiological apoptosis, a normal component of squamous differentiation.

EBM RATING

B-2.

Biology and chemoprevention of head and neck cancer

Head and neck cancer remains a common cause of mortality and morbidity in the United States and throughout the world. In spite of advances in the management of patients with advanced disease, overall survival in this group remains poor. Furthermore, although cancer mortality is lower in patients with early-stage disease, treatment results in significant morbidity, and these patients also face the risk of developing a second primary tumor. Chemoprevention is an innovative approach to decrease overall cancer morbidity and mortality using substances that are capable of preventing cancer progression. Head and neck cancer is an excellent model for chemoprevention, as its biology is consistent with the two concepts important for the development of chemoprevention strategies: field cancerization and multistep carcinogenesis. Several classes of compounds have been evaluated in chemoprevention trials. The most frequently studied agents, the retinoids, were found frequently to induce remissions in patients with oral leukoplakia. Furthermore, retinoids prevented progression to malignancy in one randomized maintenance study. Other agents, including beta-carotene and vitamin E, have been found also to have activity in the management of oral leukoplakia. However, the clinical role of chemopreventive agents in reducing cancer mortality remains to be defined. Two studies, one in head and neck cancer and one in lung cancer, have shown the ability of retinoids to prevent the development of second primary tumors. Current large randomized trials are defining the effectiveness of these agents in reducing the mortality of aerodigestive tract tumors in individuals at high risk.

Tissue markers of potentially malignant human oral epithelial lesions

Tissue markers of potential malignancy have been sought for many years. Cell surface markers, particularly blood group and histocompatibility antigens, have shown great promise and several squamous carcinoma antigens have been identified--but not fully studied in potentially malignant lesions. Growth factors and receptors also need further study. Cytoplasmic markers of potential malignancy have been examined and, of these, keratins, filaggrin, and some carcinoma antigens show most promise. Nuclear analyses have promise but are time-consuming and expensive. Image cytometric analyses appear to be sensitive and predictive: oncogene and tumour suppressor analyses remain to be fully evaluated. New investigative techniques at the cellular and molecular level show increasing promise at defining potentially malignant oral epithelial lesions but more prospective studies are required.

Diagnostic significance of nuclear DNA content and nuclear area in oral hyperplasia, dysplasia, and carcinoma

The nuclear DNA content and the nuclear area in hyperplasia, dysplasia, and carcinoma of the oral cavity were quantitatively analyzed by microspectrophotometry. In carcinoma, marked variability of the nuclear DNA content and the nuclear area was found. The mean nuclear DNA content, the variance of the nuclear DNA content, the frequency of cells above tetraploid (4 C), the mean nuclear area, and the variance of nuclear area in hyperplasia and dysplasia were significantly different from these values with carcinoma. In some cases of leukoplakia and verrucous hyperplasia with subsequent malignant formation, the values were beyond the lower limit of carcinoma. The results suggest that the nuclear DNA and the nuclear area are important objective indices for predicting malignant potential of precancerous lesions.

Which oral white lesions will become malignant? An image cytometric study

We investigated the value of image cytometry in predicting the prognosis of oral epithelial lesions, whether or not they show dysplasia. Thirty-five oral epithelial lesions were studied retrospectively. Of these, 23 had later transformed to carcinoma and 12 had not. By means of the Leitz TAS image analyzer, 200 nuclei of epithelial cells and 20 nuclei of lymphocytes from each section were individually assessed for eight features related to shape and amount of stain and for six features related to chromatin pattern. The mean, standard deviation, and interquartile range of each feature were calculated, first for each section and then for each group. With the use of linear stepwise discriminant analysis we constructed a predictive model, which consisted of three variables related to chromatin pattern. The variables were mean margination, standard deviation of clumping, and standard deviation of condensation. In the jackknife classification, this model predicted the malignant potential of the lesions that later transformed to cancer with 86% predictive value and 83% sensitivity.

Carcinoma in situ of the testis in infertile men. A histological, immunocytochemical, and cytophotometric study of DNA content

Of 723 infertile men (128 with a history of cryptorchidism) whose testes were biopsied at the outer lateral face of the testis, five presented carcinoma in situ (CIS) in one testis. These testes were removed, serially sectioned, and examined by light microscopy. In order to evaluate whether only one or two biopsies are sufficient to diagnose CIS, before sectioning the testes four biopsies were taken at the anterior face, posterior face, superior pole, and inferior pole of the testis, respectively. Two of the five men had undergone orchiopexy in infancy and the testis contained tubules with Sertoli cells and isolated spermatogonia. CIS was also present in some tubules that were principally located near the rete testis. Of the four simulated biopsies, only that performed at the posterior face of the testis revealed CIS. The other three infertile men showed tubules with complete, although reduced, spermatogenesis, and tubules lined by Sertoli cells only. CIS was found in both types of tubules. These tubules with CIS formed lobules that extended throughout the testicular parenchyma. Most simulated biopsies performed in these three testes showed CIS. The average nuclear DNA content of CIS cells was about 4c in all testes. This content was similar both in tubules with complete spermatogenesis and in tubules with Sertoli cells only.

Different responses between the upper and the lower parathyroid gland in a state of secondary hyperfunction. A study on chronic renal failure by morphometry and nuclear DNA analysis

The size of the parathyroid gland and the size, the numerical density and nuclear DNA-content of the parathyroid gland cells were evaluated in chronic renal failure (CRF) and revealed a difference between the upper and the lower glands in the manner of adaptation to a state of long-term hyperfunction, secondary to CRF. The parathyroid gland enlarged as a whole in CRF, an effect more marked in the lower gland, whereas individual parathyroid gland cell enlargement in CRF was mainly seen in the upper gland cells. The numerical density of the lower parathyroid gland cells was higher than that of the upper gland. Nuclear DNA-content of the parathyroid gland cells were increased in CRF and the lower gland tended to show hyperdiploid aneuploidy. These findings are probably related to the fact that parathyroid adenomas occur most often in the lower gland. The higher proliferative activity of the lower parathyroid gland in long-term hyperfunction may explain the higher risk for the lower gland in the occurrence of adenomas.

Prediction of malignant transformation in oral epithelial lesions by image cytometry

The value of image analysis in predicting the malignant potential of oral epithelial lesions showing either hyperplasia or dysplasia was investigated; 5-micron formalin-fixed sections of 16 oral epithelial lesions, of which eight had later transformed to carcinoma and eight had not transformed during a follow-up of 10-15 years were studied. The sections were stained with the azure A-Feulgen reaction for nuclear DNA. In each section 200 nuclei of epithelial cells and 20 nuclei of lymphocytes were assessed; all measurements were made blindly. For each nucleus six features related to shape and amount of stain and six features related to chromatin pattern were assessed. For each feature the mean, SD, and interquartile range were determined and used for linear stepwise discriminant analysis. A model of three variables with the most discriminating power was developed. When the jackknifed classification test was applied using this model, the malignant potential of the lesions that later transformed could be predicted with 87.5% accuracy.