Therapy process of personalized cancer management covers surgery, chemotherapy, radiation therapy and targeted therapies. The choice of cancer chemotherapeutic agents and doses depends upon the location and stage of tumor, as well as the general state of the patient. On the chemotherapy, radiotherapy, and targeted therapy processes, pharmacogenetics offers customized solutions according to the personal genetic information. Especially for clinicians, genetic information obtained from polymorphism-based pharmacogenetic tests is highly crucial for the better prediction ability of drug response and life-threatening toxic reactions due to the narrow therapeutic index of cancer chemotherapeutic agents. Pharmacogenotyping utilizes different examination strategies, such as single nucleotide polymorphism analysis, somatic/germline mutation analysis and partial/full genome sequencing. The promising effect of pharmacogenetics on the solving of the individual variability in drug response and toxic reactions is being observed with the accumulation of the information that unravel the human genomic variations from large-scale population and multi-parameter-based pharmacogenetic studies of the post-genomic era. Polymorphisms contribute wide variations in human genome and may define how individuals respond to medications, either by changing the pharmacokinetics and pharmacodynamics of drugs or by altering the cellular response to therapeutic agents. To define the effect of polymorphisms on the targets of chemotherapeutics is necessary for the prediction of altered pharmacokinetics of therapeutic agents.
Part of the book: Genetic Polymorphisms
With the unavoidable progress of genomics technologies, “one size fits all” strategy has switched to individual-specific treatment approaches. Hence pharmacogenomics-based personalized cancer medicine has emerged. Promising treatment option immunotherapy includes either “take the brakes off immune system (i.e., checkpoint blockade therapy) or the use of immune cells expanded in an in vitro tumor-free environment’’. Both options have been varied and included unpredictable results. Combination of cancer immunotherapy and pharmacogenomics applications may contribute to solve the complexity of outcome prediction and variations between individuals receiving the same immunotherapeutic treatment. To enhance the tumor immunity and determine cancer patients who response to immunotherapy, classification based on gene polymorphisms in key immunoregulatory molecules including antigen-presenting molecules, immunoglobulins and their receptors, cytokine/chemokines and their receptors, adhesion and costimulatory molecules, toll-like receptors, and intracellular signaling molecules plays a vital role in redirecting or modulating the function of immune cells. Therefore, polymorphisms in immunoregulatory molecules and their impact on immunotherapeutic outcome should be considered in cancer management.
Part of the book: Genetic Diversity and Disease Susceptibility
Colorectal cancer (CRC) is the third most common cancer in the world and third leading cause of cancer-related deaths in men and women as well. While early screening procedures and removal of small polyps improve the survival rates among the patients, there is still need for new diagnostic and therapeutic approaches for developing more effective treatments. MicroRNAs (miRNAs) are short noncoding RNA fragments, which involve in posttranscriptional regulation of gene expression, and they are shown to involve in tumorigenesis either targeting oncogenes or tumor suppressor genes. Based on the current studies, miRNAs are now suggested as potential biomarkers for CRC diagnosis, prognosis, and therapeutic responses. In this chapter, the latest findings on the role of miRNA in CRC in many aspects are reviewed: diagnosis (role of circular miRNAs in blood and miRNAs from tissue biopsies and their potential role in pathophysiology and diagnosis of CRC), prognosis (miRNAs related with metastasis, recurrence, and survival rates in CRC), and therapeutic responses (role of miRNAs both in chemotherapies and/or in targeted therapies in CRC). In conclusion, miRNAs are promising molecules for diagnosis, prognosis, and therapeutic responses of CRC.
Part of the book: Oncogenes and Carcinogenesis