Effect of modified neoadjuvant chemotherapy on levels of E6 oncoprotein in HPV-infected cervical tumor tissue

Background. Human papillomavirus (HPV) has been established to be the etiological factor of cervical cancer (CC). HPV infection and CC progression involve the direct participation of the E6 oncoprotein. Aim. An analysis of the E6 oncoprotein levels in tissues of the tumor and its perifocal area in HPV-associated cervical squamous cell cancer as an objective indicator of the effect of treatment depending on preoperative chemotherapy. Material and methods. The study included clinical and laboratory data of 237 patients with high-risk HPV infection of the cervix. The patients were divided into 4 groups: two main groups (CC T2а2–2bN0–1M0) and two control groups. Patients in the main group 1 (n=84) received standard neoadjuvant chemotherapy (NACT), in the main group 2 (n=93) — modified NACT with prior plasmapheresis session and a parallel course of nonspecific immunotherapy with Allokin-alpha. Control group 1 (n=40) included patients with CC T1b2–2a1N0–1M0, surgical treatment; control group 2 (n=20) — HPV-positive patients without CC. Levels of E6 were measured in samples of the cervical tumor and perifocal tissues. Results. The lowest levels of the E6 oncoprotein were registered in the group of HPV-positive patients without CC. After modified NACT, E6 levels in tumor tissues remained 4.6 times higher than in intact tissues, and even so, these patients demonstrated minimal E6 levels compared to other CC patients. E6 in tumor tissues was significantly lower than in main group 1 (by 3.3 times) and 8 times lower than in control group 1. E6 levels in the perifocal tissues of patients in main group 2 were 1.9 times lower than in the corresponding tissues of patients in main group 1 and 2.2 times lower than in control group 1. Conclusions. Inclusion of plasmapheresis and inducers of endogenous interferonogenesis into neoadjuvant treatment for cervical cancer can be considered pathogenetically justified, since it affects the key unit of cervical carcinogenesis.