Морфологія (Sep 2016)
Allocation and dynamics of inducible nitric oxide synthase expression in patients with rectal cancer under the influence of neoadjuvant chemoradiotherapy and their relationship with efficiency of polyradiomodification with the usage of L-arginine.
Abstract
Background. Considering the importance of nitric oxide in the malignant growth pathogenesis, researchers are actively exploring properties of nitric oxide synthesis biological systems in colorectal cancer tumors. However, literature data according the characteristics of iNOS expression in colorectal cancer and its prognostic and predictive value is ambiguous. Objective: to define the features of iNOS expression in intact colon and rectal cancer tissues before treatment and after the course of neoadjuvant chemoradiotherapy, including the background of the drug precursor of nitric oxide. Methods. iNOS expression indexes were determined by immunohistochemistry in the biopsy and surgical material in 24 patients with adenocarcinoma of the rectum stage II-III before and after neoadjuvant chemoradiotherapy. Results. It was revealed 4.5 times higher levels of iNOS expression in the rectal cancer tumor compared with intact mucosa. Rectal cancer iNOS is expressed in tumor parenchyma cells and in tumor stroma, the level of immunosignal in stroma is 24% higher compared with parenchyma. Positive correlation (r= 0.74; р<0.05) of iNOS expression in the tumor with metastatic lesion of regional lymph nodes was established in rectal cancer patients. High expression level of iNOS in rectal cancer tissue is a positive predictive factor for the effectiveness of radiation therapy on the background polyradiomodification using tegafur and L-arginine. Conclusion. Discovered peculiarities of iNOS expression indicate the advisability of taking into account this marker when planning neoadjuvant therapy of patients with rectal cancer and establishing the risk of disease progression.
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