P53 and PCNA expression in glandular dilatation of gastric mucosa

Yang Kun Wang, Xiao Long Ji, You Gui Gu, Shu Chun Zhang, Jian He Xiao

Subject headings gastric mucosa; precancerous conditions; stomach neoplasms; adenocarcinoma; genes, P53

Wang YK, Ji XL, Gu YG, Zhang SC, Xiao JH. P53 and PCNA expression in glandular dilatation of gastric mucosa. China Nati J New Gastroenterol, 1996;2(2):106-108

Abstract 

AIM  To study the expression of P53 and PCNA in relation to the gastric mucosa lesions.

METHODS  S-P immunohistochemical method was used to observe 92 samples of glandular dilatation of gastric mucosa and 30 cases of adenocarcinoma of stomach.

RESULTS  P53 showed no expression in simple glandular dilatation, but with small number of cell expression in atypical glandular dilatation <8.6% (5/58)¡êY,and strong expression in gastric glandular cancer <46.7% (14/30)¡êY. There were a small number of PCNA positive cells in simple glandular dilatation, and a significant increase of positive cells in atypical glandular dilatation (P<0.01), positive cells were widely distributed and deeply stained in case of gastric cancer.

CONCLUSION  It is suggested that P53 and PCNA can be jointly used as an important criterion for diagnosing, classifying and treating the precancerous lesions of gastric mucosa.



INTRODUCTIONª¥
In recent years, there have been many researches of the glandular dilatation of gastric mucosa. It was proposed that some morphological forms of gastric glandular dilatation should be related to gastric cancer; but there were also articles stating that the cystic dilatation of various degrees in gastric and pyloric glands is only a kind of alteration in the late stage of atrophic gastritisª¬ª©^£Û1-7£Ý. The glandular dilatation of gastric mucosa is commonly seen in clinical pathology, so it is necessary to distinguish the types of glandular dilatation, and find out the pathologic forms which are involved in the cancerous lesions. In this study, the S-Pimmunohistochemical method was used for comparison between 92 samples of different histologic types of glandular dilatation and 30 cases of adenocarcinoma of stomach. The assessment of P53 and PCNA expression is contributory to the clinical treatment and the research of precancerous lesions.ª¤ª¤ 

MATERIALS AND METHODS
Totally 122 samples of gastric mucosa biopsy were observed. Of them, 92 were gastric mucosa glandular dilatation and 30, the adenocarcinoma of stomach. The patients were aged in a range of 25-74 years, averaging 49.3 years. There were 72 males and 50 females. The samples were fixed in 10% formalin, embedded in paraffin. The section was 5¦Ìm in thickness, ordinarily with HE staining. Cell morphology and tissue structure were observed.ª¥Immunohistochemical staining was carried out by linking the streptomyces avidin and peroxidase. Antiª²P53 monoclonalª²antibodies (DO-7, reacting to both wild and mutant protein), antiª²PCNA and instantª²type reagent boxes were all the products of Maixi Biochemical Technology Company. DAB coloration and hematoxylin tinction were used, with PBS serving as the first antibody to make negative comparison. The positive reactions were graded into 4 grades according to the number of brown particles appearing in cell nucleus: ¢ñ=0%ª²25%, ¢ò=26%ª²50%, ¢ó=51%ª²75%, and ¢ô=76%ª²100%.ª¥
        The simple and heterotype dilatations were distinguishable, the latter included the cystadenomatoid and adenomatoid atypical hyperplasia, in accordance with the degree, form and number of the glandular dilatation, and the amount of mucus in the lumen of gland, the presence of atypical epithelioglandular cells, as well as the accompanying glandular atrophy and/or intestinal metaplasia, etc.ª¤

RESULTSª¤

Histopathology
Simple glandular dilatation was found in a small number of mild degree of focal or isolated glandular dilatation, showing an increased amount of mucus in the lumen of gland. The epithelioglandular cells were of monolayer pavement or columnar in shape; there were no atypical alteration of epithelium and no accompanying glandular atrophy and intestinal metaplasia.ª¥Atypical glandular dilatation showed cystadenoª² and adenomatoid atypical  hyperplasia.ª¥
        ¢Ù- Cystadeno-atypical proliferation showed a lot of glandular hyperplasia in cystic dilatation, in various degrees and forms, with possibly papillaª²like or branch-like structures, irregularly dilated glands, and the diameter of the big one might be several or dozens times bigger than that of the small one. Epithelial cells showed a monolayer or multilayer arrangement. Most atypical hyperplasia showed a decrease in amount of mucus in the lumen of gland, accompanied with some degree of glandular atrophy in most cases and/or with intestinal metaplasia.ª¥
    ¢Ú- Adenomatoid atypical hyperplasia: the glands were dilated in moderate degree, 4 to 6 times that of the normal size, clustered in groups, in back-to-back or in conjugated distribution; there were possible presence of intraglandular canula^£Û7£Ý, and a decrease of interstitial, epithelioglandular cells in monolayer or stratified arrangement, with a decrease of the lumen of gland; there were also possibly accompanying glandular atrophy in various degrees, with or without intestinal metaplasia.
     Immunohistochemical staining: there was no P53 expression in simple glandular dilatation but with positive expression £Û8ª±6% (5/58)£Ýin heterotypical glandular dilatation. The pattern of positive expression demonstrated a focal expression or in some cells of some dilated glandular ducts, but no positive expression in many glandular ducts in the same area; on staining density, it refers to a weak Grade ¢ñ- positive expression. In view of the expression in adenocarcinoma, the positive expression was strong, widely distributed and with deep staining, pertaining to Grade ¢ó- or Grade ¢ô-. The PCNA positive expression in simple glandular dilatation was few in number, which mostly refers to Grade ¢ñ-, while the expression with an obvious increase of cell number in heterotye dilatation, mostly refers to Grade ¢ò -or Grade ¢ó-, presenting a positive expression of many glandular ducts in one area; the positive expression of PCNA in adenocarcinoma is widely distributed, with rather deep staining which is mostly referring to an expression of Grade ¢ó- and Grade ¢ô- (Table 1).ª¤ª¤

Table 1 P53 and PCNA expression in 122 cases of gastric mucosa biopsy

DISCUSSION
The glandular dilatation of gastric mucosa may be due to many diseases, such as chronic atrophic gastritis^£Û8£Ý, gastric polypª¬ª©^£Û3£Ý, chronic ulcer^£Û9£Ý, chronic superficial gastritis and the presence of cancerous gland^£Û10£Ý, all of which may be observed characteristically in gastric mucosabiopsy. It is not a primary disease, but a dilatation with different degrees, forms and numbers. It is hence suggested that the cystic dilatation of gastric gland and pyloric gland in deep mucosa covered by the pavement of epithelial cells should  be a sign of alteration of a denatured or atrophic gastritis in advanced stage, and also that the cystic dilatations occurring in 95% of the early stage gastric cancers should be a fact closely associated with the cancerous formation. Some reports dealt with the naming of terms such as cystadeno dilatation and gastric adenocyst^£Û4,11£Ý. We believe that in the case of simply involving the cystic dilatation of glands and inflammatory infiltration, the dilated glands are small in number and in mild degree, which are possibly defined as simple glandular dilatation caused by an inflammation or a compressed jan in ducts, not belonging to a precancerous lesion. However, if there appeared the cystic dilatation, inflammatory infiltration, and the dilated glands with great numbers in severe degrees and varied forms, with epithelioglandular cells in monolayer or stratified arrangement, and nucleus in varied size, this kind of dilatation would be called the cystadeno-atypicalhyperplasia because of its cystadeno-structure and atypical epithelium, which are recognized as an important precancerous lesion. As for adenomatoid atypical hyperplasia, on which there had been few reports, the dilated glands are four to six times that of normal glands in number, clustering in groups, with interstitial decrease, and back-to-back or conjugation position, and the epithelioglandular cells display atypical hyperplasia, accompanied with glandular atrophy or intestinal metaplasia in various degrees. Because of its adenomatoid structure and epithelium atypical hyperplasia, it is called adenomatoid atypical hyperplasia, an important feature of precancerous lesion.ª¥
         Wild p53 gene is a tumor suppressor gene, playing a role in  control of cell differentiation, and preventing the abnormal growth of cells. Because of its short and unstable halfª²life, and the low concentration in cells, it can not be detected by immunohistochemical examinations; mutant ª«p53 gene product, a more stable protein product accumulated in cells having a loss of its normal function by extending its half-life, may inactivate the wild P53, so that the immunohistochemical assessment becomes a way in research of the genetic alteration of tumor. People who had excessive P53 protein expression in benign lesion accompanied with severe degree, non-typical epithelium hyperplasia, were later proved to have cancerous lesion, suggesting that there should be alteration of cells in some precancerous lesion, which can be expressed in the form of protein level^£Û12£Ý. The expression in samples of gastric mucosa biopsy in our study, is consistent with previous report. Five cases of atypical glandular dilatation of gastric mucosa showed a positive expression, but the positive cells were focal in distribution, while the simple dilatation displayed no expression. The comparison between atypical glandular dilatation and adenocarcinoma of stomach shows significant difference (P£¼0.01), indicating that P53 occurs in great number only after occurence of malignant alteration of cells, a transformation from gastric mucosa to cancer, and a role of great significance in formation of early cancer.ª¥
        PCNA is a kind of 36Mr nucleoprotein, related to the synthesis of DNA in the cell cycle. It seems that the cell is remaining in an active proliferation state, which, at present has been used as a criterion for assessment of malignant potential of a tumor in precancerous stage and  of the dynamics of tumor cells. In this series of 92 samples of biopsy, the expression in glandular dilatation of gastric mucosa is increased with the rising of the active level of the cell proliferation. The comparison between the simple glandular dilatation and the atypical one is significantly different (P£¼0.01). In gastric cancer, the positive expression is widely distributed and deep in tinction. PCNA is an important criterion for the diagnosis, classification and treatment of precancerous lesion.ª¤ª¤

^£±Dr. Wang Yangª²Kun, having 59 papers published. Department of Pathology, Chinese PLA 150 Hospital, Luoyang 471031,
Henan Province, China.ª¤
²Dr. JI Xiao-Long, Department of Pathology, Chinese PLA General Hospital, Beijing 100853, China.
Correspondence to Dr. Wang Yang Kun,Department of Pathology, Chinese PLA 150 Hospital, Luoyang 471031,
Henan Province, China.
Received -20 October 1995,revised -10 February 1996.