Carcinoma of the stomach is one of most prevalent cancer types in the world today. It is considered a major killer worldwide; therefore it remains a global health problem. Recent studies suggest that proliferating activity may provide important prognostic information in different types of tumours. Ki-67 and PCNA are the two most frequently used cell proliferation markers. The practical implications of this phenomenon in gastric cancer prognosis or early detection are under study. The aim of the study:1.To assess the immunohistochemical expression of ki-67 and PCNA in gastric carcinoma & to correlate this with various clinicopathological parameters including: age, gender of patients, site, histological type, gross appearance, grade and stage of the tumor in gastric carcinoma . 2. To assess the correlation between ki-67 and PCNA in gastric carcinoma. Patients, materials and methods: A retrospective study from( may2008-junory 2009) included the collection of fourty formalin fixed paraffin embedded gastric carcinoma tissue specimen from the archived materials of the Center of Gastrointestinal and Hepatic Diseases, and other private laboratories, covering the period from 2000- 2008DC. Clinicopathological parameters including: age, gender of patients, site, histological type, grade and stage of the tumor in gastric carcinoma were obtained from the available histopathological reports. For each case four micrometer-thickness tissue sections were obtained, one section was stained with Hematoxylin and Eosin & diagnosis has been revised, while two sections were stained immunohistochemically for ki-67 and PCNA. Brownish staining nucleus of the tumor tissue was regarded as positive ki67 and PCNA expression. Statistical analysis was performed using chi-square test, t –test and ANOVAs test for tables with frequencies, percentages, mean and standard deviation. Values were considered statistically significant when P<0.05. Results:Regarding gender distribution there was 24 male patients and 16 female patients. The age of patients ranged between30-80 years with a (mean ± SD) of (55.68±14.47) years. Tacking in consideration the tumor location, 32(80%) were located in the antral region while the remaining 8(20%) were located in the cardia. The commonest histological type was the intestinal type 34(85%).The 24(60%) of the gastric carcinoma cases were moderately differentiated. The gastric carcinoma cases 33(82.50%) fall in stage III disease.The overall expression of ki-67 in gastric carcinoma cases in the present study was 29(72.5%). Cases which were in age group above or equal to 50 years 19(67.85%) and 10(83.35) cases in age group below50 years.
Cases of gastric carcinoma with positive ki-67 expression showed male predominance 18 (75%) compared to female 11 (68.75%) cases. Tumor cells with positive ki-67 immunostaining 7 (87.5%) were located in the cardial region; the remaining positive ki-67immunostaining 22(86.75%) cases were located in the antral region. Intestinal type gastric carcinoma showed the higher ki-67 expression 25 (73.52%) compared to diffuse type gastric carcinoma 4(66.67%). The ki-67 expression was more in poorly differentiated12 (75%) gastric cancer than moderately type17 (70.83%). Regarding the stage of gastric carcinoma, stage IV disease were 6(85.71%) while stage III were 23 (69.70%). There was no statistically significant difference in the relationship between ki-67 expression with age, gender of patients, gross, histological type, tumor grade and tumor stage (P>0.05) But there was statistically significant difference in the relationship between ki-67 expression with the tumor site. Regarding PCNA expression in gastric carcinoma cases in the present study was35(87.5%) . 24(85.71%)cases were in age group above or equal to 50 years and11 (91.67%) cases were in the age group below50 years. Cases of gastric carcinoma with positive PCNA expression showed female predominance 15 (93.75%) cases compared to male 20 (83.3%).Tumor with positive PCNA immunostaining were located in the antral region 30 (93.8%), & 5 (62.5%) of cardic tumor showed positive PCNA expression.Diffuse type gastric carcinoma showed the higher PCNA expression 6(100%). compared to intestinal type gastric carcinoma 29 (85.3%) Poorly- differentiated gastric carcinoma cases with positive PCNA expression were 16 (100%), while the remaining cases 19(79.2%) were moderately - differentiated.
Cases of gastric carcinoma in stage IV showed a positive PCNA expression in 7 (100%). There was no statistically significant correlation between PCNA expression and the age, gender of patients, gross& histological type of gastric carcinoma (P>0.05). But there was a statistically significant correlation between PCNA expression and the site, grade and tumor stage. Conclusion:The overall expression of ki-67in gastric carcinoma cases in this IHC study was 72.5% and 87.5% for PCNA. There was no significant correlation between ki-67 expression and different clinicopathological variables including: age, gender of patients, histological type, tumor stage and grade. But there was statistically significant difference in the relationship between ki-67 expression with the site, while PCNA there was significant correlation with the site, grade and tumor stage. Finally there was no significant correlation between ki-67 and PCNA expression in gastric carcinoma cases.