Radiation therapy or radiotherapy is a treatment using ionizing radiation, generally provided as part of cancer therapy to either kill or control the growth of malignant cells. It is normally delivered by a linear particle accelerator. Radiation therapy may be curative in a number of types of cancer if they are localized to one area of the body, and have not spread to other parts. It may also be used as part of adjuvant therapy, to prevent tumor recurrence after surgery to remove a primary malignant tumor. Radiation therapy is synergistic with chemotherapy, and has been used before, during, and after chemotherapy in susceptible cancers. The subspecialty of oncology concerned with radiotherapy is called radiation oncology. A physician who practices in this subspecialty is a radiation oncologist.
Tumor hypoxia is the situation where tumor cells have been deprived of oxygen. As a tumor grows, it rapidly outgrows its blood supply, leaving portions of the tumor with regions where the oxygen concentration is significantly lower than in healthy tissues. Hypoxic microenvironments in solid tumors are a result of available oxygen being consumed within 70 to 150 μm of tumor vasculature by rapidly proliferating tumor cells thus limiting the amount of oxygen available to diffuse further into the tumor tissue. In order to support continuous growth and proliferation in challenging hypoxic environments, cancer cells are found to alter their metabolism. Furthermore, hypoxia is known to change cell behavior and is associated with extracellular matrix remodeling and increased migratory and metastatic behavior.
A clonogenic assay is a cell biology technique for studying the effectiveness of specific agents on the survival and proliferation of cells. It is frequently used in cancer research laboratories to determine the effect of drugs or radiation on proliferating tumor cells as well as for titration of Cell-killing Particles (CKPs) in virus stocks. It was first developed by T.T. Puck and Philip I. Marcus at the University of Colorado in 1955.
A glioma is a type of primary tumor that starts in the glial cells of the brain or spinal cord. They are cancerous but some are extremely slow to develop. Gliomas comprise about 30 percent of all brain tumors and central nervous system tumours, and 80 percent of all malignant brain tumours.
In medicine, proton therapy, or proton radiotherapy, is a type of particle therapy that uses a beam of protons to irradiate diseased tissue, most often to treat cancer. The chief advantage of proton therapy over other types of external beam radiotherapy is that the dose of protons is deposited over a narrow range of depth; hence in minimal entry, exit, or scattered radiation dose to healthy nearby tissues.
Radiosurgery is surgery using radiation, that is, the destruction of precisely selected areas of tissue using ionizing radiation rather than excision with a blade. Like other forms of radiation therapy, it is usually used to treat cancer. Radiosurgery was originally defined by the Swedish neurosurgeon Lars Leksell as "a single high dose fraction of radiation, stereotactically directed to an intracranial region of interest".
Dose fractionation effects are utilised in the treatment of cancer with radiation therapy. When the total dose of radiation is divided into several, smaller doses over a period of several days, there are fewer toxic effects on healthy cells. This maximizes the effect of radiation on cancer and minimizes the negative side effects. A typical fractionation scheme divides the dose into 30 units delivered every weekday over six weeks.
An eye neoplasm is a tumor of the eye. A rare type of tumor, eye neoplasms can affect all parts of the eye, and can either be benign or malignant (cancerous), in which case it is known as eye cancer. Eye cancers can be primary or metastatic cancer. The two most common cancers that spread to the eye from another organ are breast cancer and lung cancer. Other less common sites of origin include the prostate, kidney, thyroid, skin, colon and blood or bone marrow.
Fast neutron therapy utilizes high energy neutrons typically between 50 and 70 MeV to treat cancer. Most fast neutron therapy beams are produced by reactors, cyclotrons (d+Be) and linear accelerators. Neutron therapy is currently available in Germany, Russia, South Africa and the United States. In the United States, one treatment center is operational, in Seattle, Washington. The Seattle center uses a cyclotron which produces a proton beam impinging upon a beryllium target.
The radiation-induced bystander effect is the phenomenon in which unirradiated cells exhibit irradiated effects as a result of signals received from nearby irradiated cells. In November 1992, Hatsumi Nagasawa and John B. Little first reported this radiobiological phenomenon.
Particle therapy is a form of external beam radiotherapy using beams of energetic neutrons, protons, or other heavier positive ions for cancer treatment. The most common type of particle therapy as of August 2021 is proton therapy.
Exposure to ionizing radiation is known to increase the future incidence of cancer, particularly leukemia. The mechanism by which this occurs is well understood, but quantitative models predicting the level of risk remain controversial. The most widely accepted model posits that the incidence of cancers due to ionizing radiation increases linearly with effective radiation dose at a rate of 5.5% per sievert; if correct, natural background radiation is the most hazardous source of radiation to general public health, followed by medical imaging as a close second. Additionally, the vast majority of non-invasive cancers are non-melanoma skin cancers caused by ultraviolet radiation. Non-ionizing radio frequency radiation from mobile phones, electric power transmission, and other similar sources have been investigated as a possible carcinogen by the WHO's International Agency for Research on Cancer, but to date, no evidence of this has been observed.
Randy Jirtle is an American biologist noted for his research in epigenetics, the branch of biology that deals with inherited information that does not reside in the nucleotide sequence of DNA. Jirtle retired from Duke University, Durham, NC in 2012. He is presently Professor of Epigenetics in the Department of Biological Sciences at North Carolina State University, Raleigh, NC. Jirtle is noted for his research on genomic imprinting, and for his use of the Agouti mouse model to investigate the effect of environmental agents on the mammalian epigenome and disease susceptibility.
DEP Domain Containing Protein 1B also known as XTP1, XTP8, HBV XAg-Transactivated Protein 8, [formerly referred to as BRCC3] is a human protein encoded by a gene of similar name located on chromosome 5.
C11orf52 is an uncharacterized protein that in homo sapiens is encoded by the C11orf52 gene.
Cilia- and flagella-associated protein 299 (CFAP299) is a protein that in humans is encoded by the CFAP299 gene. CFAP299 is predicted to play a role in spermatogenesis and cell apoptosis.
Chromosome 11 open reading frame 53 is a protein that in humans is encoded by the C11orf53 gene. Reduction in C11orf53 gene expression is associated with increased odds of occurrence of colorectal cancer. Specifically sequence variation (rs3802842) close to the C11orf53 gene locus that lowers the expression of C11orf53 has been observed in the colonic mucosal cells immediately adjacent to colon cancer tumors. C11orf53 downregulation aids in cells' ability to survive in acidic conditions, which are typical of the tumor microenvironment. CRISPR-Cas9 inactivation of C11orf53 in an acute myeloid leukemia cell line made the cells resistant to the BCL2 inhibitor Venetoclax, further supporting a role in cancer predisposition.
C12orf29 is a protein that in humans is encoded by chromosome 12 open reading frame 29. The gene is ubiquitously expressed in various tissues. The protein has 325 amino acids. The biological process of C12orf29 has been annotated as hematopoietic progenitor cell differentiation. The molecular and cellular functions of C12orf29 gene have not yet well understood by the scientific community.
Protein Njmu-R1 is a protein that in humans is encoded by the C17orf75 gene. C17orf75 is also known as SRI2 and is a human protein encoding gene located at 17q11.2 on the complementary strand. The C17orf75 gene is ubiquitously expressed at medium-low levels throughout the body and at slightly higher levels in the brain and testes. This protein is thought to be part of a complex associated with Golgi-mediated vesicle capture.
Kelch-like Homolog 28 (KLHL28) is a protein that is encoded by the KLHL28 gene in humans. It is a member of the Kelch-like gene family, which comprises 42 different genes. Aberrant activation of KLHL28 results in increased likelihood of hypertension, hyperkalemia, and cancer. The KLHL28 gene, also known as BTBD5, has orthologs in vertebrates and some marine invertebrates, and has been well-conserved over evolutionary timescales.
