The presence of A5935G, G5949A, G6081A, G6267A, T9540C mutations in MT-CO1 and MT-CO3 genes and other variants of MT-CO1 and MT-CO3 gene fragments in the study population diagnosed with endometrial cancer

Objectives: The specific purpose of this study was the assessment of A5935G, G5949A, G6081A, G6267A mutations in MT-CO1 and T9540C in MT-CO3, and alterations detected during the analysis of MT-CO gene fragments in subject and control groups. A secondary aim was to assess the relationship between MT-CO1 and MT-CO3 gene alterations and endometrial cancer incidence and evaluation of the prognostic value of MT-CO1 and MT-CO3 gene alterations. Material and methods: In this study, we investigated A5935G, G5949A, G6081A, G6267A mutations in MT-CO1 and T9540C in MT-CO3, and alterations detected during the analysis of MT-CO gene fragments in formalin-fixed, paraffin-embedded endometrial and benign endometrial hyperplasia of a cohort of 125 subjects. Results: The T9540C mutation in MT-CO3 was detected in one patient from the subject group. None of the remaining muta­tions were detected. The research showed that the presence of alterations in MT-CO1 and MT-CO3 typical of other types of cancer is not a risk factor for endometrial cancer. Analysis of MT-CO1 and MT-CO3 gene fragments revealed 10 alterations (6 and 4 respectively). The alterations detected were identified in 10% of the tested group and 8% of the control group. Conclusions: The research showed that the presence of alterations in MT-CO1 (A5935G, G5949A, G6081A, G6267A) typical of other types of cancer is not a risk factor for endometrial cancer. Three new alterations detected in this study (A6052G, A9545G, G9575A) were described for the first time

Mitochondrial dysfunction in cancer

Mitochondria are semi-autonomous organelles of eukaryotic cells. They perform crucial functions such as generating most of the cellular energy through the oxidative phosphorylation (OXPHOS) system and some other metabolic processes. In addition, mitochondria are involved in regulation of cell death and reactive oxygen species (ROS) generation. Also, mitochondria play important roles in carcinogenesis via altering energy metabolism, resistance to apoptosis, increase of production of ROS and mtDNA (mitochondrial genome) changes. Studies have suggested that aerobic glycolysis is high in malignant tumors. Probably, it correlates with high glucose intake of cancerous tissues. This observation is contrary to Warburg’s theory that the main way of energy generation in cancer cells is non-oxidative glycolysis. Further studies have suggested that in tumor cells both oxidative phosphorylation and glycolysis were active at various rates. An increase of intracellular oxidative stress induces damage of cellular structure and somatic mutations. Further studies confirmed that permanent activity of oxidative stress and the influence of chronic inflammation damage the healthy neighboring epithelium and may lead to carcinogenesis. For instance, chronic inflammato­ry bowel disease could be related to high risk of colon adenocarcinoma. The data have shown a role of ROS generation, mtDNA or nDNA alterations and abnormal apoptotic machinery in endometrial cancer progress. Recent studies suggest that mtDNA mutations might play a potential role in endometrial cancer progress and indicate an increase of mitochondrial biogenesis in this cancer. The investigators suggested that MtCOI and MtND6 alteration has an influence on assembly of respiratory complexes in endometrial cancer. In many human cancers, there is a deregulation of the balance between cell growth and death. The tumor cells can avoid apoptosis through a loss of balance between anti- and pro-apoptotic proteins, reduced caspase function and impaired death receptor signaling. Over-expression of the anti-apoptotic BCL-2 gene has also been identified in numerous cancers including colon, thyroid, breast and endometrial cancer. Most studies have found low BCL-2 family gene expression, which could be a sign of blocking apoptosis in breast and endometrial cancer. Moreover, BCL-2 gene expression is correlated with the degree of aggressiveness and differentiation in endometrial cancer. As a result, it could be a valuable predictor of disease progression

The significance of markers in the diagnosis of endometrial cancer

Endometrial cancer is one of the most common cancers experienced by women throughout the world. It is also the most common malignancy within the female reproductive system, representing 37.7% of all disorders. The incidence increases with age, and is diagnosed most frequently in women between 45 and 65 years old. In the last few years, numerous studies have been performed to identify tumour biomarkers. Biomarkers include not only protein routinely used as tumour markers but also genes and chromosomes. The limiting factor in the use of markers in the diagnosis of endometrial cancer is their lack of specificity. However, specific markers for endometrial cancer are the subject of much research attention. Although moderately elevated levels of markers are present in a number of inflammatory or non-malignant diseases, significantly increased levels of markers indicate the development of cancer. Recently, research has been focused on the identification of molecular changes leading to different histological subtypes of endometrial cancer. In this paper the authors reviewed several currently investigated markers. Progress in these investigations is very important in the diagnostics and treatment of endometrial cancer. In particular, the identification of novel mutations and molecular profiles should enhance our ability to personalise adjuvant treatment with genome-guided targeted therapy