The mitochondria are essential for normal cell functioning. Changes in mitochondrial DNA (mtDNA) may affect the occurrence of some chronic diseases and cancer. This process is complex and not entirely understood. The assignment to a particular mitochondrial haplogroup may be a factor that either contributes to cancer development or reduces its likelihood. Mutations in mtDNA occurring via an increase in reactive oxygen species may favour the occurrence of further changes both in mitochondrial and nuclear DNA. Mitochondrial DNA mutations in postmitotic cells are not inherited, but may play a role both in initiation and progression of cancer. One of the first discovered polymorphisms associated with cancer was in the gene NADH-ubiquinone oxidoreductase chain 3 (mt-ND3) and it was typical of haplogroup N. In prostate cancer, these mutations and polymorphisms involve a gene encoding subunit I of respiratory complex IV cytochrome c oxidase subunit 1 gene (COI). At present, a growing number of studies also address the impact of mtDNA polymorphisms on prognosis in cancer patients. Some of the mitochondrial DNA polymorphisms occur in both chronic disease and cancer, for instance polymorphism G5913A characteristic of prostate cancer and hypertension.

Lung cancer is the leading cause of death worldwide for both men and women. Surgery can be offered as a radical treatment at stages I and II and selected cases of stage III (III A). Whereas at more advanced stages, combined modalities of treatment are applied: radiochemotherapy (IIIB) and molecularly targeted treatment (small molecule tyrosine kinase inhibitors, VEGF receptor inhibitors, monoclonal antibodies, and immunological treatment with monoclonal antibodies). Combination treatment, composed of radiotherapy and molecular therapy, is increasingly employed in locally advanced and metastatic lung cancer management. Recent studies have indicated a synergistic effect of such treatment and modification of immune response. The combination of immunotherapy and radiotherapy may result in the enhancement of the abscopal effect. Anti-angiogenic therapy, in combination with RT, is associated with high toxicity and should be not recommended. In this paper, the authors discuss the role of molecular treatment and the possibility of its concurrent use with radiotherapy in non-small cell lung cancer (NSCLC).

Background: Eyelid tumors are rare skin cancers, the most common of which is basal cell carcinoma characterized primarily by local growth. In addition to surgery, radiotherapy is among the basic methods of treatment. External beam radiotherapy is associated with the risk of complications within ocular structures, especially the lens. In the case of interstitial brachytherapy, it is possible to administer a high dose to the clinical target volume (CTV), while reducing it in the most sensitive structures. Methods: This paper presents the results of an analysis of 28 patients treated with interstitial high dose rate (HDR) brachytherapy for skin cancers of the upper and lower eyelid; medial and lateral canthus; and the cheek, nose and temples with the infiltration of ocular structures. The patients were treated according to two irradiation schedules: 49 Gy in 14 fractions of 3.5 Gy twice a day for 7 days of treatment, and 45 Gy in 5 Gy fractions twice a day for 5 days. The mean follow-up was 22 months (3–49 months). Results: two patients (6%) had a relapse: a local recurrence within the irradiated area in one of them, and metastases to lymph nodes in the other. The most common early complication was conjunctivitis (74%), and the most common late complication was dry eye syndrome (59%). Conclusions: Interstitial HDR brachytherapy for skin cancers of the upper and lower eyelid; medial and lateral cants; and the cheek, nose and temples with infiltration of ocular structures is a highly effective, short and relatively low burden type of treatment.

Changes in cell signaling pathways, which in normal conditions determine the maintenance of cell homeostasis and the correctness of its basic processes, may cause the transformation of a normal cell into a cancer cell. Alterations in cellular metabolism leading to oncogenesis are considered to be a hallmark of cancer cells. Therefore, a thorough understanding of cellular enzymes affecting metabolism and respiration, as well as intracellular pathways connected with them, seems crucial. These changes may be both prognostic and predictive factors, especially in terms of using molecularly targeted therapies. Aberrations in the pathways responsible for cell growth and angiogenesis are considered particularly important in the process of oncogenesis. Gliomas are the most common primary malignant tumors of the brain. The most important molecular disorders determining their particularly malignant nature are aberrations in the pathways responsible for cell growth and angiogenesis, such as the PI3K/Akt or RAS/MAPK/ERK signaling pathway, as well as excessive activity of enzymes, like hexokinases, which play a key role in glycolysis, autophagy, and apoptosis. The multitude of alterations detected in glioma cells, high heterogeneity, and the immunosuppressive environment within the tumor are the main features causing failures in the attempts to implement modern therapies.

Mitochondrial DNA changes can contribute to both an increased and decreased likelihood of cancer. This process is complex and not fully understood. Polymorphisms and mutations, especially those of the missense type, can affect mitochondrial functions, particularly if the conservative domain of the protein is concerned. This study aimed to identify the possible relationships between brain gliomas and the occurrence of specific mitochondrial DNA polymorphisms and mutations in respiratory complexes III, IV and V. The investigated material included blood and tumour material collected from 30 Caucasian patients diagnosed with WHO grade II, III or IV glioma. The mitochondrial genetic variants were investigated across the mitochondrial genome using next-generation sequencing (MiSeq/FGx system—Illumina). The study investigated, in silico, the effects of missense mutations on the biochemical properties, structure and functioning of the encoded protein, as well as their potential harmfulness. The A14793G (MTCYB), A15758G, (MT-CYB), A15218G (MT-CYB), G7444A (MT-CO1) polymorphisms, and the T15663C (MT-CYB) and G8959A (ATP6) mutations were assessed in silico as harmful alterations that could be involved in oncogenesis. The G8959A (E145K) ATP6 missense mutation has not been described in the literature so far. In light of these results, further research into the role of mtDNA changes in brain tumours should be conducted.

The ability to undergo neoangiogenesis is a common feature with all cancers. Signaling related to vascular endothelial growth factors (VEGF) and their receptors (VEGFR) plays a key role in the process of tumor neoangiogenesis. A close relationship has been demonstrated between excessive VEGF levels and the induction of immunosuppression in the tumor microenvironment. The use of drugs blocking the VEGF function, apart from the anticancer effect, also result in adverse effects, in particular related to the circulatory system and kidneys. Cardiac toxicity associated with the use of such therapy manifests itself mainly in the form of hypertension, thromboembolic episodes and ischemic heart disease. In the case of renal complications, the most common symptoms include renal arterial hypertension, proteinuria and microangiopathy. Although these complications are reversible in 60–80% of cases after cessation of VSP (VEGF pathway inhibitor) therapy, in some cases they can lead to irreversible changes in renal function, whereas cardiac complications may be fatal. Also, the use of PD-1/PD-L1 inhibitors may result in kidney and heart damage. In the case of cardiac complications, the most common symptoms include myocarditis, pericarditis, arrhythmia, acute coronary syndrome and vasculitis, while kidney damage most often manifests as acute kidney injury (AKI), nephrotic syndrome, pyuria or hematuria. The decision whether to resume treatment after the occurrence of cardiovascular and renal complications remains a problem.