Objective: The role of the c-myc proto-oncogene in genomic instability is just becoming more fully understood. However, its role in endometrial cancer is essentially unknown. The objective of this study was to determine the relationship between cytoplasmic and nuclear c-myc staining, DNA index, and survival in patients with endometrial carcinoma.
Methods: One hundred and twenty-one patients with endometrial carcinoma were studied. Image analysis was used to determine DNA index. In addition to cytoplasmic and nuclear c-myc staining and DNA index, histologic type, stage, grade, depth of invasion, lymphvascular space invasion, and peritoneal cytology were evaluated as prognostic indicators. Univariate and multivariate analyses were performed.
Results: One hundred and twenty-one patients were followed for over 5 years. c-myc cytoplasmic staining was present in 75.2% of the patients' tumors, and nuclear staining was present in 66.9% (P = 0.99). DNA index was significantly higher in patients with nuclear c-myc staining and no cytoplasmic staining (DNA index 1.38) as compared to those patients whose tumors displayed cytoplasmic c-myc staining but no nuclear c-myc staining (1.18) (P = 0.016). Patients whose tumors stained positively for nuclear c-myc and negatively for cytoplasmic c-myc had significantly worse survival by Kaplan-Meier analysis (P < 0.0001). Seventeen patients died during the follow-up period of this study. By multivariate analysis, positive cytoplasmic c-myc staining with negative nuclear staining (P = 0.0076), negative cytoplasmic c-myc staining with positive nuclear staining (P = 0.011) and FIGO stage (P < 0.0001) were shown to be independent prognostic indicators predictive of survival.
Conclusion: Nuclear and cytoplasmic c-myc staining, as well as FIGO stage, when assessed by multivariate analysis, were demonstrated to be important factors in predicting survival in the 121 patients in this study. While increasing FIGO stage was prognostic of decreased survival, the specific location of c-myc staining was also associated with prognosis. The expression of the c-myc protein is related to survival in patients with adenocarcinoma of the endometrium.