Reprimo (RPRM), is a gene located at human chromosome 2q23 whose expression in conjunction with p53, along with other genes which are p53-induced, is associated with the arrest of the cell cycle at the G2 phase. [1] [2] Reprimo's protein product is a highly glycosylated polypeptide which, upon its expression, is localized to the cytoplasm where it is primarily active. [2] As the expression of reprimo is controlled by p53, which is in turn controlled by a wide array of convergent signal pathways pertaining to DNA damage or nutrient depravity, its presence is expected within cells which would cause damage should they be freely allowed to replicate. [2] Pursuant to this, reprimo's expression during the G2 phase of the cell cycle ultimately results in the reduction of Cdc2 expression, and in the inhibition of the nuclear translocation of cyclin B1 which is necessary to its function. [1] Reprimo is known to collaborate with p21 to achieve these specific effects, [2] and in a more general sense collaborates with the other p53-induced proteins and effectors to produce the overall cellular response. These regulatory actions help to render the afflicted cell into an arrested state which is less immediately threatening to the whole organism due to the inability of afflicted cells to replicate with damaged DNA, among other potential circumstances, giving the cell an opportunity to undergo DNA repair or apoptosis as the level of damage will dictate. Indefinite cell cycle arrest is another potential outcome. For this reason, it is considered to be a tumor suppressor gene. [3]
Identification of this gene's repression via methylation to its upstream promoter region [2] [4] within various types of cancerous tissue have been used to suggest a connection to the formation of said cancer.[ citation needed ] These methylation events commonly cause aberrant DNA splicing which may cause one of many potential errors within the resulting mutant reprimo that ultimately undermine its ability to be expressed, have its intended effects, or to accumulate in sufficient quantities to produce the expected arrest reaction. [2] The variability of these outcomes is owed to the large probability space for these point mutations. There is also research to suggest that this gene's expression status within specific tissues may be useful information for the diagnosis or prognosis of certain types of cancer. [3]
In those whom have already been diagnosed with primary pancreatic cancer, there is a correlative relationship to suggest there will be a much worse prognosis when said tissues were found to contain these methylations to reprimo's promoter. [4]
In terms of early detection, the methylation status of reprimo in esophageal and gastric tissues have had some success in predicting the development of cancer. [5] [6] In the case of gastric cancer, detection methods include sampling of blood plasma.[ citation needed ]
A tumor suppressor gene (TSG), or anti-oncogene, is a gene that regulates a cell during cell division and replication. If the cell grows uncontrollably, it will result in cancer. When a tumor suppressor gene is mutated, it results in a loss or reduction in its function. In combination with other genetic mutations, this could allow the cell to grow abnormally. The loss of function for these genes may be even more significant in the development of human cancers, compared to the activation of oncogenes.
ATM serine/threonine kinase or Ataxia-telangiectasia mutated, symbol ATM, is a serine/threonine protein kinase that is recruited and activated by DNA double-strand breaks, oxidative stress, topoisomerase cleavage complexes, splicing intermediates, R-loops and in some cases by single-strand DNA breaks. It phosphorylates several key proteins that initiate activation of the DNA damage checkpoint, leading to cell cycle arrest, DNA repair or apoptosis. Several of these targets, including p53, CHK2, BRCA1, NBS1 and H2AX are tumor suppressors.
Carcinogenesis, also called oncogenesis or tumorigenesis, is the formation of a cancer, whereby normal cells are transformed into cancer cells. The process is characterized by changes at the cellular, genetic, and epigenetic levels and abnormal cell division. Cell division is a physiological process that occurs in almost all tissues and under a variety of circumstances. Normally, the balance between proliferation and programmed cell death, in the form of apoptosis, is maintained to ensure the integrity of tissues and organs. According to the prevailing accepted theory of carcinogenesis, the somatic mutation theory, mutations in DNA and epimutations that lead to cancer disrupt these orderly processes by interfering with the programming regulating the processes, upsetting the normal balance between proliferation and cell death. This results in uncontrolled cell division and the evolution of those cells by natural selection in the body. Only certain mutations lead to cancer whereas the majority of mutations do not.
Cyclin B is a member of the cyclin family. Cyclin B is a mitotic cyclin. The amount of cyclin B and the activity of the cyclin B-Cdk complex rise through the cell cycle until mitosis, where they fall abruptly due to degradation of cyclin B. The complex of Cdk and cyclin B is called maturation promoting factor or mitosis promoting factor (MPF).
Survivin, also called baculoviral inhibitor of apoptosis repeat-containing 5 or BIRC5, is a protein that, in humans, is encoded by the BIRC5 gene.
DNA mismatch repair protein Msh2 also known as MutS homolog 2 or MSH2 is a protein that in humans is encoded by the MSH2 gene, which is located on chromosome 2. MSH2 is a tumor suppressor gene and more specifically a caretaker gene that codes for a DNA mismatch repair (MMR) protein, MSH2, which forms a heterodimer with MSH6 to make the human MutSα mismatch repair complex. It also dimerizes with MSH3 to form the MutSβ DNA repair complex. MSH2 is involved in many different forms of DNA repair, including transcription-coupled repair, homologous recombination, and base excision repair.
Checkpoint kinase 1, commonly referred to as Chk1, is a serine/threonine-specific protein kinase that, in humans, is encoded by the CHEK1 gene. Chk1 coordinates the DNA damage response (DDR) and cell cycle checkpoint response. Activation of Chk1 results in the initiation of cell cycle checkpoints, cell cycle arrest, DNA repair and cell death to prevent damaged cells from progressing through the cell cycle.
G2/mitotic-specific cyclin-B1 is a protein that in humans is encoded by the CCNB1 gene.
Methylated-DNA--protein-cysteine methyltransferase(MGMT), also known as O6-alkylguanine DNA alkyltransferaseAGT, is a protein that in humans is encoded by the MGMT gene. MGMT is crucial for genome stability. It repairs the naturally occurring mutagenic DNA lesion O6-methylguanine back to guanine and prevents mismatch and errors during DNA replication and transcription. Accordingly, loss of MGMT increases the carcinogenic risk in mice after exposure to alkylating agents. The two bacterial isozymes are Ada and Ogt.
Secreted frizzled-related protein 1, also known as SFRP1, is a protein which in humans is encoded by the SFRP1 gene.
Growth arrest and DNA-damage-inducible protein GADD45 gamma is a protein that in humans is encoded by the GADD45G gene on chromosome 9. GADD45G is also known as CR6, DDIT2, GRP17, OIG37, and GADD45gamma. GADD45G is involved in several different processes, including sexual development, human-specific brain development, tumor suppression, and the cellular stress response. GADD45G interacts with several other proteins that are involved in DNA repair, cell cycle control, apoptosis, and senescence. Low expression of GADD45G has been associated with many types of cancer.
Ribonucleotide-diphosphate reductase subunit M2 B is an enzyme that in humans is encoded by the RRM2B gene. The gene encoding the RRM2B protein is located on chromosome 8, at position 8q23.1. The gene and its products are also known by designations MTDPS8A, MTDPS8B, and p53R2.
Protein CIP2A also known as cancerous inhibitor of PP2A (CIP2A) is a protein that in humans is encoded by the KIAA1524 gene.
Transcriptional repressor CTCFL also known as BORIS is a protein that in humans is encoded by the CTCFL gene.
Transcription factor AP-2 gamma also known as AP2-gamma is a protein that in humans is encoded by the TFAP2C gene. AP2-gamma is a member of the activating protein 2 family of transcription factors.
Cancer epigenetics is the study of epigenetic modifications to the DNA of cancer cells that do not involve a change in the nucleotide sequence, but instead involve a change in the way the genetic code is expressed. Epigenetic mechanisms are necessary to maintain normal sequences of tissue specific gene expression and are crucial for normal development. They may be just as important, if not even more important, than genetic mutations in a cell's transformation to cancer. The disturbance of epigenetic processes in cancers, can lead to a loss of expression of genes that occurs about 10 times more frequently by transcription silencing than by mutations. As Vogelstein et al. points out, in a colorectal cancer there are usually about 3 to 6 driver mutations and 33 to 66 hitchhiker or passenger mutations. However, in colon tumors compared to adjacent normal-appearing colonic mucosa, there are about 600 to 800 heavily methylated CpG islands in the promoters of genes in the tumors while these CpG islands are not methylated in the adjacent mucosa. Manipulation of epigenetic alterations holds great promise for cancer prevention, detection, and therapy. In different types of cancer, a variety of epigenetic mechanisms can be perturbed, such as the silencing of tumor suppressor genes and activation of oncogenes by altered CpG island methylation patterns, histone modifications, and dysregulation of DNA binding proteins. There are several medications which have epigenetic impact, that are now used in a number of these diseases.
DNA damage is an alteration in the chemical structure of DNA, such as a break in a strand of DNA, a nucleobase missing from the backbone of DNA, or a chemically changed base such as 8-OHdG. DNA damage can occur naturally or via environmental factors, but is distinctly different from mutation, although both are types of error in DNA. DNA damage is an abnormal chemical structure in DNA, while a mutation is a change in the sequence of base pairs. DNA damages cause changes in the structure of the genetic material and prevents the replication mechanism from functioning and performing properly. The DNA damage response (DDR) is a complex signal transduction pathway which recognizes when DNA is damaged and initiates the cellular response to the damage.
Prognostic markers are biomarkers used to measure the progress of a disease in the patient sample. Prognostic markers are useful to stratify the patients into groups, guiding towards precise medicine discovery. The widely used prognostic markers in cancers include stage, size, grade, node and metastasis. In addition to these common markers, there are prognostic markers specific to different cancer types. For example estrogen level, progesterone and HER2 are markers specific to breast cancer patients. There is evidence showing that genes behaving as tumor suppressors or carcinogens could act as prognostic markers due to altered gene expression or mutation. Besides genetic biomarkers, there are also biomarkers that are detected in plasma or body fluid which can be metabolic or protein biomarkers.
TSPY like 5 is a protein that in humans is encoded by the TSPYL5 gene.
Reprimo-like (RPRML) is a vertebrate gene located at human chromosome 17q21.32. It is a member of the Reprimo gene family which consists of two human-related protein-coding and intronless genes: Reprimo (RPRM) and RPRML. Although poorly characterized, this lineage has been implicated in important developmental and cancer processes.