What is hereditary prostate cancer?

Cancer development is a complex process. If certain genes are mutated and do not give cells proper instructions about when to grow and divide, then cancer could develop. Environmental factors, such as UV light, tobacco and diet can increase mutation rates. Some of these mutations will be repaired, but some mutations will not. These mutations will be present in some cells in the body and this will increase the risk of cancer development.

However in families with hereditary forms of cancer, a mutation is present in a very important gene and is present in all cells in the body. Inheriting a cancer-causing mutation in one of the cancer-associated genes does not mean that cancer will definitely occur. It means only that your risk is higher than for someone who does not carry such a mutation in their cells.

Prostate cancer is the second most common cancer among men in the United States. According to the National Institute of Health, about 1 in 7 men will be diagnosed with prostate cancer at some point in their life, with more than 60% of men diagnosed after age 65. African American men have a higher risk of developing prostate cancer than white males do. Approximately 10% of prostate cancers are hereditary. The same mutations in cancer predisposing genes that increase the risk of breast and ovarian cancer in women, also increase the chance of prostate cancer and male breast cancer in men. And fathers are just as likely to pass the risk for breast and ovarian cancer to their daughters, as are their mothers. Men carrying a pathogenic mutation in the BRCA1 or BRCA2 gene have an increased risk of prostate cancer, pancreatic cancer, and male breast cancer (Table 1).



What is hereditary prostate cancer?

You could have an inherited risk if:

  • 3 or more first-degree relatives diagnosed with prostate cancer at any age
  • Prostate cancer seen in 3 generations on the same side of the family
  • 2 or more close family members (i.e brother, father, grandfather) on the same side of the family diagnosed with prostate cancer before 55.

What is ProstateDx ClearTM?

ProstateDx ClearTM is a multi-gene test that analyses point mutations, gross deletions and duplications in the following genes associated with inherited prostate, breast, colorectal and some other types of cancer: ATM, BRCA1, BRCA2, BRIP1, CHEK2, EPCAM, MLH1, MRE11A, MSH2, MSH6, NBN, PALB2, PMS2, RAD51C, RAD51D and TP53. We use next-generation sequencing (NGS) technology to identify variants in the coding regions of these genes. The identified variants are classified according to the guidelines for sequence variant interpretation of the American College of Medical Genetics and Genomics (ACMG). Variant classification categories include pathogenic, likely pathogenic, variant of unknown significance (VUS), likely benign, and benign.

  • Pathogenic variants - Genetic changes with known clinical significance that is associated with an increased risk of hereditary cancer.
  • Likely pathogenic variants – Genetic changes that have some preliminary clinical data indicating an association with hereditary cancer but not sufficient to make a definitive determination of pathogenicity.
  • Variants of uncertain significance (VUS) – Genetic changes with either conflicting or no supporting data to determine their pathogenicity.
  • Negative Result – No variant of clinical or uncertain significance was detected. Negative result does not eliminate the risk of developing cancer.

Benign variants that have sufficient evidence to be considered of no clinical significance and likely benign variants that are not likely to increase the risk of cancer will not be shown on the report.


What are the possible benefits of ProstateDx Clear testing?

Any hereditary cancer susceptibility testing reduces the uncertainty about the risks of cancer for people and their families. Such testing may be able to explain the cancer history in your family. If a cancer predisposing mutation is identified, it can help your doctor to guide your medical care and decrease the risk of prostate and other associated cancers.


ProstateDx ClearTM genes, Associated Cancers and Characteristics

ProstateDx ClearTM is a multi-gene test that analyzes 16 prostate cancer susceptibility genes ( listed below ). Although all males (especially after age 50) have some risk of developing prostate cancer at some point in their lives, having a mutation in one of the prostate cancer susceptibility genes increases this risk. Men who have a mutation in one of the prostate cancer susceptibility genes also have an increased risk of pancreatic, gastric, male breast and other cancer types.

GENE LIST
ATM BRCA1 BRCA2 BRIP1 CHEK2 EPCAM MLH1 MRE11A
MSH2 MSH6 NBN PALB2 PMS2 RAD51C RAD51D TP53
Click on any gene to view its definition

ATM - The ATM gene provides instructions for making a protein that is located primarily in the nucleus of cells, where it helps control the rate at which cells grow and divide. This protein also plays an important role in the normal development and activity of several body systems, including the nervous system and the immune system. Additionally, the ATM protein assists cells in recognizing damaged or broken DNA strands. DNA can be damaged by agents such as toxic chemicals or radiation. Breaks in DNA strands also occur naturally when chromosomes exchange genetic material during cell division. The ATM protein coordinates DNA repair by activating enzymes that fix the broken strands. Efficient repair of damaged DNA strands helps maintain the stability of the cell's genetic information.

BRCA1 - This gene provides instructions for making a protein that acts as a tumor suppressor. Tumor suppressor proteins help prevent cells from growing and dividing too rapidly or in an uncontrolled way.

The BRCA1 protein is involved in repairing damaged DNA. In the nucleus of many types of normal cells, the BRCA1 protein interacts with several other proteins to mend breaks in DNA. These breaks can be caused by natural and medical radiation or other environmental exposures, and they also occur when chromosomes exchange genetic material in preparation for cell division. By helping to repair DNA, the BRCA1 protein plays a critical role in maintaining the stability of a cell's genetic information.

Research suggests that the BRCA1 protein also regulates the activity of other genes and plays an essential role in embryonic development. To carry out these functions, the BRCA1 protein interacts with many other proteins, including other tumor suppressors and proteins that regulate cell division.

BRCA2 - This gene provides instructions for making a protein that acts as a tumor suppressor. Tumor suppressor proteins help prevent cells from growing and dividing too rapidly or in an uncontrolled way.

The BRCA2 protein is involved in repairing damaged DNA. In the nucleus of many types of normal cells, the BRCA2 protein interacts with several other proteins to mend breaks in DNA. These breaks can be caused by natural and medical radiation or other environmental exposures, and they also occur when chromosomes exchange genetic material in preparation for cell division. By helping to repair DNA, the BRCA2 protein plays a critical role in maintaining the stability of a cell's genetic information.

Researchers suspect that the BRCA2 protein has additional functions within cells. For example, the protein may help regulate cytokinesis, which is the step in cell division when the fluid surrounding the nucleus (the cytoplasm) divides to form two separate cells. Researchers are investigating the protein's other potential activities.

BRIP1 - The protein encoded by this gene is a member of the RecQ DEAH helicase family and interacts with the BRCT repeats of breast cancer, type 1 (BRCA1). The bound complex is important in the normal double-strand break repair function of breast cancer, type 1 (BRCA1). This gene may be a target of germline cancer-inducing mutations

CHEK2 - The CHEK2 gene provides instructions for making a protein called checkpoint kinase 2 (CHK2). This protein acts as a tumor suppressor, which means that it regulates cell division by keeping cells from growing and dividing too rapidly or in an uncontrolled way.

The CHK2 protein is activated when DNA becomes damaged or when DNA strands break. DNA can be damaged by agents such as toxic chemicals, radiation, or ultraviolet (UV) rays from sunlight, and breaks in DNA strands also occur naturally when chromosomes exchange genetic material.

In response to DNA damage, the CHK2 protein interacts with several other proteins, including tumor protein 53 (which is produced from the TP53 gene). These proteins halt cell division and determine whether a cell will repair the damage or self-destruct in a controlled manner (undergo apoptosis). This process keeps cells with mutated or damaged DNA from dividing, which helps prevent the development of tumors.

EPCAM - This gene provides instructions for making a protein known as epithelial cellular adhesion molecule (EpCAM). This protein is found in epithelial cells, which are the cells that line the surfaces and cavities of the body. The EpCAM protein is found spanning the membrane that surrounds epithelial cells, where it helps cells stick to one another (cell adhesion). In addition, the protein in the cell membrane can be cut at a specific location, releasing a piece called the intracellular domain (EpICD), which helps relay signals from outside the cell to the nucleus of the cell. EpICD travels to the nucleus and associates with other proteins, forming a group (complex) that regulates the activity of several genes that are involved in cell growth and division (proliferation), maturation (differentiation), and movement (migration), all of which are important processes for the proper development of cells and tissues.

MLH1 This gene provides instructions for making a protein that plays an essential role in DNA repair. This protein helps fix mistakes that are made when DNA is copied (DNA replication) in preparation for cell division. The MLH1 protein joins with another protein called PMS2 (produced from the PMS2 gene), to form a protein complex. This complex coordinates the activities of other proteins that repair mistakes made during DNA replication. The repairs are made by removing a section of DNA that contains mistakes and replacing the section with a corrected DNA sequence. The MLH1 gene is a member of a set of genes known as the mismatch repair (MMR) genes.

MRE11A - This gene encodes a nuclear protein involved in homologous recombination, telomere length maintenance, and DNA double-strand break repair. By itself, the protein has 3' to 5' exonuclease activity and endonuclease activity. The protein forms a complex with the RAD50 homolog; this complex is required for nonhomologous joining of DNA ends and possesses increased single-stranded DNA endonuclease and 3' to 5' exonuclease activities. In conjunction with a DNA ligase, this protein promotes the joining of noncomplementary ends in vitro using short homologies near the ends of the DNA fragments. This gene has a pseudogene on chromosome 3. Alternative splicing of this gene results in two transcript variants encoding different isoforms.

MSH2 - This gene provides instructions for making a protein that plays an essential role in DNA repair. This protein helps fix mistakes that are made when DNA is copied (DNA replication) in preparation for cell division. The MSH2 protein joins with one of two other proteins, MSH6 or MSH3 (each produced from a different gene), to form a protein complex. This complex identifies locations on the DNA where mistakes have been made during DNA replication. Another group of proteins, the MLH1-PMS2 protein complex, then repairs the errors. The MSH2 gene is a member of a set of genes known as the mismatch repair (MMR) genes.

MSH6 - This gene provides instructions for making a protein that plays an essential role in repairing DNA. This protein helps fix mistakes that are made when DNA is copied (DNA replication) in preparation for cell division. The MSH6 protein joins with another protein called MSH2 (produced from the MSH2 gene) to form a protein complex. This complex identifies locations on the DNA where mistakes have been made during DNA replication. Another group of proteins, the MLH1-PMS2 protein complex, then repairs the errors. The MSH6 gene is a member of a set of genes known as the mismatch repair (MMR) genes.

NBN - This gene provides instructions for making a protein called nibrin. This protein is involved in several critical cellular functions, including the repair of damaged DNA.

Nibrin interacts with two other proteins, produced from the MRE11A and RAD50 genes, as part of a larger protein complex. Nibrin regulates the activity of this complex by carrying the MRE11A and RAD50 proteins into the cell's nucleus and guiding them to sites of DNA damage. The proteins work together to mend broken strands of DNA. DNA can be damaged by agents such as toxic chemicals or radiation, and breaks in DNA strands also occur naturally when chromosomes exchange genetic material in preparation for cell division. Repairing DNA prevents cells from accumulating genetic damage that may cause them to die or to divide uncontrollably.

The MRE11A/RAD50/NBN complex interacts with the protein produced from the ATM gene, which plays an essential role in recognizing broken strands of DNA and coordinating their repair. The MRE11A/RAD50/NBN complex helps maintain the stability of a cell's genetic information through its roles in repairing damaged DNA and regulating cell division. Because these functions are critical for preventing the formation of cancerous tumors, nibrin is described as a tumor suppressor.

PALB2 - This gene encodes a protein that may function in tumor suppression. This protein binds to and colocalizes with the breast cancer 2 early onset protein (BRCA2) in nuclear foci and likely permits the stable intranuclear localization and accumulation of BRCA2.

PMS2 - This gene provides instructions for making a protein that plays an essential role in repairing DNA. This protein helps fix mistakes that are made when DNA is copied (DNA replication) in preparation for cell division. The PMS2 protein joins with another protein called MLH1 (produced from the MLH1 gene) to form a protein complex. This complex coordinates the activities of other proteins that repair mistakes made during DNA replication. Repairs are made by removing the section of DNA that contains mistakes and replacing it with a corrected DNA sequence. The PMS2 gene is a member of a set of genes known as the mismatch repair (MMR) genes.

RAD51C - This gene is a member of the RAD51 family. RAD51 family members are highly similar to bacterial RecA and Saccharomyces cerevisiae Rad51 and are known to be involved in the homologous recombination and repair of DNA. This protein can interact with other RAD51 paralogs and is reported to be important for Holliday junction resolution. Mutations in this gene are associated with Fanconi anemia-like syndrome. This gene is one of four localized to a region of chromosome 17q23 where amplification occurs frequently in breast tumors. Overexpression of the four genes during amplification has been observed and suggests a possible role in tumor progression. Alternative splicing results in multiple transcript variants.

RAD51D - The protein encoded by this gene is a member of the RAD51 protein family. RAD51 family members are highly similar to bacterial RecA and Saccharomyces cerevisiae Rad51, which are known to be involved in the homologous recombination and repair of DNA. This protein forms a complex with several other members of the RAD51 family, including RAD51L1, RAD51L2, and XRCC2. The protein complex formed with this protein has been shown to catalyze homologous pairing between single- and double-stranded DNA, and is thought to play a role in the early stage of recombinational repair of DNA. Alternative splicing results in multiple transcript variants. Read-through transcription also exists between this gene and the downstream ring finger and FYVE-like domain containing 1 (RFFL) gene.

TP53 - This gene provides instructions for making a protein called tumor protein p53 (or p53). This protein acts as a tumor suppressor, which means that it regulates cell division by keeping cells from growing and dividing too fast or in an uncontrolled way.

The p53 protein is located in the nucleus of cells throughout the body, where it attaches (binds) directly to DNA. When the DNA in a cell becomes damaged by agents such as toxic chemicals, radiation, or ultraviolet (UV) rays from sunlight, this protein plays a critical role in determining whether the DNA will be repaired or the damaged cell will self-destruct (undergo apoptosis). If the DNA can be repaired, p53 activates other genes to fix the damage. If the DNA cannot be repaired, this protein prevents the cell from dividing and signals it to undergo apoptosis. By stopping cells with mutated or damaged DNA from dividing, p53 helps prevent the development of tumors.

Because p53 is essential for regulating cell division and preventing tumor formation, it has been nicknamed the "guardian of the genome."