Assessment of HER-2/neu, с-MYC and CCNE1 gene copy number variations and protein expression in endometrial carcinomas

To analyze copy number variations of HER-2/neu, c-MYC and CCNE1 oncogenes and their protein expression in endometrioid endometrial carcinomas in relation to the degree of tumor progression and presence of a family history of cancer in cancer patients.

The study was conducted on endometrial cancer (EC) samples from 68 patients with I-II FIGO stages of disease. Copy number analysis of HER-2/neu, c-MYC and CCNE1 genes was performed by quantitative PCR. Protein expression was analyzed using immunohistochemistry.

Assessment of copy number variations of HER-2/neu, c-MYC and CCNE1 genes revealed their amplification in the tumors of 18.8, 25.0 and 14.3% of EC patients, respectively. High expression of corresponding proteins was detected in 14.6, 23.5 and 65.6% of patients, respectively. It was established that HER-2/neu gene amplification is more common in the group of tumors of low differentiation grade than in moderate grade EC (35.7 and 5.5% of cases, respectively, p < 0.05). Also, high expression of c-Myc protein was more frequently observed in low differentiated tumors compared to the moderately differentiated EC (36.6 and 13.2% of cases, respectively, p < 0.05). Expression of HER-2/neu and cyclin E proteins was found to be dependent on the depth of tumor invasion into the myometrium. High expression of HER-2/neu protein was observed in 25.0 and 4.1% of EC patients with tumor invasion > ½ and < ½ of the myometrium, respectively, and cyclin E - in 86.7 and 46.6% of cases, respectively, p < 0.05. It was shown that among patients with a family history of cancer, a larger proportion of cases with high expression of c-Myc protein was observed compared to the group of patients with sporadic tumors (43.8 and 17.3%, respectively; p < 0.05).

Amplification of HER-2/neu gene, along with high expression of c-Myc, HER-2/neu and cyclin E proteins, are associated with such indices of tumor progression as a low differentiation grade and deep myometrial invasion, suggesting the potential possibility of including these markers in the panel for determining the molecular EC subtype associated with an aggressive course of the disease. In a certain category of EC patients, there is a relationship between a family history of cancer and high expression of c-Myc protein.