A Family in Need Internet-enhanced Case Study on Cancer Genetics Answers

Description

Breast cancer is a disease in which certain cells in the breast become abnormal and multiply uncontrollably to form a tumor. Although breast cancer is much more than common in women, this form of cancer tin also develop in men. In both women and men, the near mutual form of breast cancer begins in cells lining the milk ducts (ductal cancer). In women, cancer can too develop in the glands that produce milk (lobular cancer). Most men accept little or no lobular tissue, then lobular cancer in men is very rare.

In its early on stages, chest cancer commonly does not cause hurting and may exhibit no noticeable symptoms. As the cancer progresses, signs and symptoms tin include a lump or thickening in or near the breast; a change in the size or shape of the chest; nipple discharge, tenderness, or retraction (turning inward); and peel irritation, dimpling, redness, or scaliness. However, these changes can occur as function of many different conditions. Having one or more than of these symptoms does not mean that a person definitely has breast cancer.

In some cases, cancerous cells can invade surrounding breast tissue. In these cases, the condition is known equally invasive breast cancer. Sometimes, tumors spread to other parts of the body. If breast cancer spreads, cancerous cells most ofttimes appear in the bones, liver, lungs, or brain. Tumors that brainstorm at i site so spread to other areas of the torso are called metastatic cancers.

A small pct of all breast cancers cluster in families. These cancers are described as hereditary and are associated with inherited gene mutations. Hereditary chest cancers tend to develop earlier in life than noninherited (desultory) cases, and new (primary) tumors are more than likely to develop in both breasts.

Frequency

Chest cancer is the second nearly commonly diagnosed cancer in women. (Only skin cancer is more common.) Well-nigh 1 in 8 women in the The states volition develop invasive chest cancer in her lifetime. Researchers estimate that more than 276,000 new cases of invasive breast cancer will be diagnosed in U.South. women in 2020.

Male person breast cancer represents less than 1 percent of all breast cancer diagnoses. Scientists approximate that about 2,600 new cases of breast cancer will be diagnosed in men in 2020.

Particular gene mutations associated with breast cancer are more common among certain geographic or indigenous groups, such as people of Ashkenazi (central or eastern European) Jewish heritage and people of Norwegian, Icelandic, or Dutch ancestry.

Causes

Cancers occur when a buildup of mutations in disquisitional genes—those that control cell growth and division or repair damaged Dna—allow cells to grow and divide uncontrollably to grade a tumor. In most cases of chest cancer, these genetic changes are acquired during a person's lifetime and are present but in sure cells in the breast. These changes, which are chosen somatic mutations, are not inherited. Somatic mutations in many different genes take been found in breast cancer cells. Less commonly, gene mutations present in essentially all of the trunk's cells increment the adventure of developing breast cancer. These genetic changes, which are classified as germline mutations, are usually inherited from a parent. In people with germline mutations, changes in other genes, together with environmental and lifestyle factors, also influence whether a person will develop breast cancer.

Some breast cancers that cluster in families are associated with inherited mutations in particular genes, such as BRCA1 or BRCA2. These genes are described every bit "loftier penetrance" because they are associated with a high take a chance of developing breast cancer and ovarian cancer and a moderate risk of developing pancreatic cancer and a type of pare cancer called melanoma in women who take mutations. Men with mutations in these genes also have an increased risk of developing several forms of cancer, including breast cancer, pancreatic cancer, prostate cancer, and melanoma. The proteins produced from the BRCA1 and BRCA2 genes are involved in fixing damaged DNA, which helps to maintain the stability of a cell'south genetic information. They are described as tumor suppressors considering they help keep cells from growing and dividing too fast or in an uncontrolled way. Mutations in these genes impair Deoxyribonucleic acid repair, allowing potentially damaging mutations to persist in Dna. Equally these defects accumulate, they can trigger cells to grow and divide without control or club to course a tumor.

A significantly increased risk of breast cancer is likewise a feature of several rare genetic syndromes. These include Cowden syndrome, which is near often caused by mutations in the PTEN gene; hereditary diffuse gastric cancer, which results from mutations in the CDH1 gene; Li-Fraumeni syndrome, which is ordinarily caused past mutations in the TP53 gene; and Peutz-Jeghers syndrome, which typically results from mutations in the STK11 gene. The proteins produced from these genes act equally tumor suppressors. Mutations in whatever of these genes can allow cells to grow and divide unchecked, leading to the development of a cancerous tumor. Similar BRCA1 and BRCA2, these genes are considered "loftier penetrance" because mutations greatly increment a person'due south chance of developing cancer. In addition to chest cancer, mutations in these genes increase the gamble of several other types of cancer over a person'due south lifetime. Some of the conditions too include other signs and symptoms, such equally the growth of noncancerous (benign) tumors.

Mutations in dozens of other genes take been studied equally possible risk factors for breast cancer. These genes are described as "low penetrance" or "moderate penetrance" because changes in each of these genes appear to make simply a small-scale or moderate contribution to overall chest cancer risk. Some of these genes provide instructions for making proteins that interact with the proteins produced from the BRCA1 or BRCA2 genes. Others act through unlike pathways. Researchers suspect that the combined influence of variations in these genes may significantly impact a person'south risk of developing breast cancer.

In many families, the genetic changes associated with hereditary chest cancer are unknown. Identifying boosted genetic risk factors for breast cancer is an active surface area of medical inquiry.

Researchers accept identified many personal and ecology factors that contribute to a person'south risk of developing breast cancer. These factors include sex, age, ethnic background, a history of previous breast cancer, certain changes in chest tissue, and hormonal and reproductive factors. A history of breast cancer in closely related family members is also an important take chances cistron, particularly if the cancer occurred in early adulthood. In addition, exposure to cancer-causing compounds (carcinogens) can increase the charge per unit at which somatic mutations occur, contributing to a person's run a risk of developing breast cancer.

Inheritance

About cases of breast cancer are non caused past inherited genetic factors. These cancers are associated with somatic mutations in breast cells that are caused during a person'southward lifetime, and they do not cluster in families.

In hereditary chest cancer, the way that cancer risk is inherited depends on the factor involved. For case, mutations in the BRCA1 and BRCA2 genes are inherited in an autosomal dominant pattern, which means one re-create of the contradistinct cistron in each jail cell is sufficient to increase a person's chance of developing cancer. Although chest cancer is more than common in women than in men, the mutated gene tin be inherited from either the female parent or the male parent.

In the other syndromes discussed in a higher place, the gene mutations that increase cancer risk also have an autosomal dominant pattern of inheritance. Information technology is important to note that people inherit an increased likelihood of developing cancer, not the illness itself. Not all people who inherit mutations in these genes volition ultimately develop cancer.

In many cases of breast cancer that clusters in families, the genetic basis for the disease and the mechanism of inheritance are unclear.

Other Names for This Status

• Chest cancer, familial
• Breast carcinoma
• Cancer of chest
• Malignant neoplasm of chest
• Malignant tumor of breast
• Mammary cancer

References

• American Cancer Society: Cancer Facts and Statistics
• Apostolou P, Fostira F. Hereditary breast cancer: the era of new susceptibility genes. Biomed Res Int. 2013;2013:747318. doi: 10.1155/2013/747318. Epub 2013 Mar 21. Review. Commendation on PubMed or Free commodity on PubMed Central
• Economopoulou P, Dimitriadis G, Psyrri A. Beyond BRCA: new hereditary breast cancer susceptibility genes. Cancer Treat Rev. 2015 Jan;41(1):1-8. doi: ten.1016/j.ctrv.2014.10.008. Epub 2014 November 6. Review. Citation on PubMed
• Filippini SE, Vega A. Breast cancer genes: beyond BRCA1 and BRCA2. Front end Biosci (Landmark Ed). 2013 Jun 1;18(4):1358-72. Review. Citation on PubMed
• Foulkes WD. BRCA1 and BRCA2 - update and implications on the genetics of breast cancer: a clinical perspective. Clin Genet. 2014 Jan;85(i):1-4. doi: 10.1111/cge.12291. Epub 2013 Oct 25. Review. Erratum in: Clin Genet. 2014 Mar;85(3):302. Citation on PubMed
• National Cancer Institute: Genetics of Breast and Gynecologic Cancers (PDQ®)–Health Professional Version
• Njiaju UO, Olopade OI. Genetic determinants of chest cancer take chances: a review of electric current literature and problems pertaining to clinical application. Breast J. 2012 Sep;18(5):436-42. doi: 10.1111/j.1524-4741.2012.01274.x. Review. Citation on PubMed
• Petrucelli N, Daly MB, Pal T. BRCA1- and BRCA2-Associated Hereditary Chest and Ovarian Cancer. 1998 Sep 4 [updated 2022 Feb three]. In: Adam MP, Ardinger HH, Pagon RA, Wallace SE, Bean LJH, Gripp KW, Mirzaa GM, Amemiya A, editors. GeneReviews® [Net]. Seattle (WA): University of Washington, Seattle; 1993-2022. Available from http://world wide web.ncbi.nlm.nih.gov/books/NBK1247/ Citation on PubMed
• Shiovitz S, Korde LA. Genetics of chest cancer: a topic in evolution. Ann Oncol. 2015 Jul;26(7):1291-9. doi: x.1093/annonc/mdv022. Epub 2015 Jan 20. Review. Citation on PubMed or Free commodity on PubMed Central
• Tung N, Battelli C, Allen B, Kaldate R, Bhatnagar Due south, Bowles K, Timms K, Garber JE, Herold C, Ellisen Fifty, Krejdovsky J, DeLeonardis Thousand, Sedgwick K, Soltis K, Roa B, Wenstrup RJ, Hartman AR. Frequency of mutations in individuals with breast cancer referred for BRCA1 and BRCA2 testing using adjacent-generation sequencing with a 25-factor panel. Cancer. 2015 January one;121(1):25-33. doi: x.1002/cncr.29010. Epub 2014 Sep 3. Citation on PubMed

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Source: https://medlineplus.gov/genetics/condition/breast-cancer/

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