Hereditary diffuse gastric cancer | |
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Other names | HDGC |
Diagram demonstrating the end result of a total gastrectomy, the most common prophylactic treatment of HDGC. In the procedure the esophagus is directly connected to the small intestine. | |
Specialty | Oncology, Gastroenterology |
Complications | Lobular breast cancer |
Usual onset | 38 years of age (median) |
Causes | Mutation of the E-cadherin gene (CDH1) |
Risk factors | Stomach cancer |
Treatment | Total gastrectomy |
Frequency | 1-3% of gastric cancers |
Hereditary diffuse gastric cancer (HDGC) is an inherited genetic syndrome most often caused by an inactivating mutation in the E-cadherin gene (CDH1) located on chromosome 16. [1] Individuals who inherit an inactive copy of the CDH1 gene are at significantly elevated risk for developing stomach cancer. For this reason, individuals with these mutations will often elect to undergo prophylactic gastrectomy, or a complete removal of the stomach to prevent this cancer. [1] Mutations in CDH1 are also associated with high risk of lobular breast cancers, and may be associated with a mildly elevated risk of colon cancer. [2]
The most common form of stomach cancer associated with CDH1 mutations is diffuse-type adenocarcinoma. An estimated 70% of males and 56% of females who inherit an inactivating CDH1 mutation will develop this form of cancer by age 80. Female patients are also estimated to have a 42% lifetime risk of developing lobular breast cancer. [3] The median age of gastric cancer diagnosis in individuals with a CDH1 inactivating mutation is 38 years of age, but cases have been reported as young as 14 years of age. [4]
Hereditary diffuse gastric cancer is inherited as an autosomal dominant mutation of the E-cadherin gene (CDH1), which is located on chromosome 16q22.1. Because the condition only conveys significantly increased risk of cancer, it can be described as having incomplete penetrance. [3]
The autosomal dominant nature of the mutations implies that inheriting just one mutated copy of the CDH1 gene is sufficient to induce a disease state. However, in order for cancer to arise in these individuals, both copies of the CDH1 gene must be inactive. Therefore, HDGC is developed through a loss of heterozygosity, in which the one unmutated copy of the CDH1 gene undergoes mutation or inactivation in some cells during the lifetime of the individual. This explains why the majority of individuals with CDH1 mutations will develop clinical apparent cancer, but some do not. [3]
The gene mutated in HDGC, CDH1, codes for the E-cadherin protein. This protein serves numerous functions in cell-to-cell interactions, as well as intracellular signaling. Development of cancerous cells and malignancy may be related to several of these functions. One major function includes cell-cell adhesion facilitated by E-cadherin binding. Loss of this function may lead to dedifferentiation of cells and/or unregulated cell growth and replication. Another major function includes binding and sequestering of the beta-catenin transcription factor, keeping it inactive. Loss of this function may lead to overactivity of the transcription factor. [5]
Genetic counseling and testing for CDH1 mutations are advised for families meeting the following criteria: [6]
Although CDH1 is by far the most common gene associated with HDGC, around 11% of cases arise in individuals who are negative for mutations in this gene. No other gene has been proven to cause HDGC, but possible associated genes include CTNNA1 , BRCA2 , STK11 , SDHB , PRSS1 , ATM , MSR1 , and PALB2 . [5]
Surgical removal of the stomach (gastrectomy) is typically recommended for people after 20 years of age, and before 40 years of age in order to prevent development of diffuse gastric adenocarcinoma. However, individuals discovering CDH1 mutations after the age of 40 may still be considered for gastrectomy. The physical and psychological health of each individual should be considered in determining the optimal time to perform this operation. Younger individuals may wish to delay this procedure, and are often monitored with endoscopies and random biopsies. In addition, all individuals testing positive receive an initial endoscopy, at which any lesion is biopsied, as gastric cancer frequently begins without symptoms. [5]
Females with CDH1 mutations also have an elevated risk of lobular breast carcinoma. Frequent screening for breast cancer with both mammography and breast MRI is common and recommended for these individuals. [7]
The risk of colon cancer in those with CDH1 mutations is still unclear. Due to the mild risk that may be associated, individuals often receive screening colonoscopies at age 40, five years prior to the recommendation in the general population. [3]
The median age at diagnosis is 38 years. An estimated 1-3% of gastric cancers are associated with hereditary cancer syndromes. HDGC is the most common hereditary cancer syndrome of the stomach. [4]
HDGC was originally discovered through studies of Maori families in New Zealand that were noted to have increased incidences of gastric cancer. [2] Detection of CDH1 mutations causing HDGC is highest in countries with low incidences of gastric cancer, such as the United States and Canada. Conversely, detection of CDH1 mutations is lowest in countries with high rates of gastric cancer, such as Portugal, Italy, and Japan. [8] For this reason, some have pushed for increased genetic screening in countries with high rates of gastric cancer, as the rates may mask the incidence of CDH1 mutations. [9]
Stomach cancer, also known as gastric cancer, is a cancer that develops from the lining of the stomach. Most cases of stomach cancers are gastric carcinomas, which can be divided into a number of subtypes, including gastric adenocarcinomas. Lymphomas and mesenchymal tumors may also develop in the stomach. Early symptoms may include heartburn, upper abdominal pain, nausea, and loss of appetite. Later signs and symptoms may include weight loss, yellowing of the skin and whites of the eyes, vomiting, difficulty swallowing, and blood in the stool, among others. The cancer may spread from the stomach to other parts of the body, particularly the liver, lungs, bones, lining of the abdomen, and lymph nodes.
Li–Fraumeni syndrome is a rare, autosomal dominant, hereditary disorder that predisposes carriers to cancer development. It was named after two American physicians, Frederick Pei Li and Joseph F. Fraumeni, Jr., who first recognized the syndrome after reviewing the medical records and death certificates of 648 childhood rhabdomyosarcoma patients. This syndrome is also known as the sarcoma, breast, leukaemia and adrenal gland (SBLA) syndrome.
Linitis plastica is a widely used term for Brinton's disease, a morphological variant of diffuse stomach cancer. In some texts, the term is also used to describe the condition of a rigid, non-distensible stomach which may be caused by a non-malignant condition such as a caustic injury to the stomach.
Familial adenomatous polyposis (FAP) is an autosomal dominant inherited condition in which numerous adenomatous polyps form mainly in the epithelium of the large intestine. While these polyps start out benign, malignant transformation into colon cancer occurs when they are left untreated. Three variants are known to exist, FAP and attenuated FAP are caused by APC gene defects on chromosome 5 while autosomal recessive FAP is caused by defects in the MUTYH gene on chromosome 1. Of the three, FAP itself is the most severe and most common; although for all three, the resulting colonic polyps and cancers are initially confined to the colon wall. Detection and removal before metastasis outside the colon can greatly reduce and in many cases eliminate the spread of cancer.
A germline mutation, or germinal mutation, is any detectable variation within germ cells. Mutations in these cells are the only mutations that can be passed on to offspring, when either a mutated sperm or oocyte come together to form a zygote. After this fertilization event occurs, germ cells divide rapidly to produce all of the cells in the body, causing this mutation to be present in every somatic and germline cell in the offspring; this is also known as a constitutional mutation. Germline mutation is distinct from somatic mutation.
Cadherins (named for "calcium-dependent adhesion") are cell adhesion molecules important in forming adherens junctions that let cells adhere to each other. Cadherins are a class of type-1 transmembrane proteins, and they depend on calcium (Ca2+) ions to function, hence their name. Cell-cell adhesion is mediated by extracellular cadherin domains, whereas the intracellular cytoplasmic tail associates with numerous adaptors and signaling proteins, collectively referred to as the cadherin adhesome.
Hereditary nonpolyposis colorectal cancer (HNPCC) or Lynch syndrome is an autosomal dominant genetic condition that is associated with a high risk of colon cancer as well as other cancers including endometrial cancer, ovary, stomach, small intestine, hepatobiliary tract, upper urinary tract, brain, and skin. The increased risk for these cancers is due to inherited genetic mutations that impair DNA mismatch repair. It is a type of cancer syndrome. Because patients with Lynch syndrome can have polyps, the term HNPCC has fallen out of favor.
Birt–Hogg–Dubé syndrome (BHD), also Hornstein–Birt–Hogg–Dubé syndrome, Hornstein–Knickenberg syndrome, and fibrofolliculomas with trichodiscomas and acrochordons is a human, adult onset, autosomal dominant genetic disorder caused by the FLCN gene. It can cause susceptibility to kidney cancer, renal and pulmonary cysts, and noncancerous tumors of the hair follicles, called fibrofolliculomas. The symptoms seen in each family are unique, and can include any combination of the three symptoms. Fibrofolliculomas are the most common manifestation, found on the face and upper trunk in over 80% of people with BHD over the age of 40. Pulmonary cysts are equally common (84%), but only 24% of people with BHD eventually experience a collapsed lung. Kidney tumors, both cancerous and benign, occur in 14–34% of people with BHD; the associated kidney cancers are often rare hybrid tumors.
Cowden syndrome is an autosomal dominant inherited condition characterized by benign overgrowths called hamartomas as well as an increased lifetime risk of breast, thyroid, uterine, and other cancers. It is often underdiagnosed due to variability in disease presentation, but 99% of patients report mucocutaneous symptoms by age 20–29. Despite some considering it a primarily dermatologic condition, Cowden's syndrome is a multi-system disorder that also includes neurodevelopmental disorders such as macrocephaly.
Fundic gland polyposis is a medical syndrome where the fundus and the body of the stomach develop many fundic gland polyps. The condition has been described both in patients with familial adenomatous polyposis (FAP) and attenuated variants (AFAP), and in patients in whom it occurs sporadically.
Hereditary breast–ovarian cancer syndromes (HBOC) are cancer syndromes that produce higher than normal levels of breast cancer, ovarian cancer and additional cancers in genetically related families. It accounts for 90% of the hereditary cancers. The hereditary factors may be proven or suspected to cause the pattern of breast and ovarian cancer occurrences in the family. The name HBOC may be misleading because it implies that this genetic susceptibility to cancer is mainly in women. In reality, both sexes have the same rates of gene mutations and HBOC can predispose to other cancers including prostate cancer and pancreatic cancer. For this reason, the term "King syndrome" has recently come into use. The new name references Mary-Claire King who identified the genes BRCA1 and BRCA2.
The tumor suppressor gene FLCN encodes the protein folliculin, also known as Birt–Hogg–Dubé syndrome protein, which functions as an inhibitor of Lactate Dehydrogenase-A and a regulator of the Warburg effect. Folliculin (FLCN) is also associated with Birt–Hogg–Dubé syndrome, which is an autosomal dominant inherited cancer syndrome in which affected individuals are at risk for the development of benign cutaneous tumors (folliculomas), pulmonary cysts, and kidney tumors.
Signet ring cell carcinoma (SRCC) is a rare form of highly malignant adenocarcinoma that produces mucin. It is an epithelial malignancy characterized by the histologic appearance of signet ring cells.
Cadherin-1 or Epithelial cadherin(E-cadherin), is a protein that in humans is encoded by the CDH1 gene. Mutations are correlated with gastric, breast, colorectal, thyroid, and ovarian cancers. CDH1 has also been designated as CD324. It is a tumor suppressor gene.
Male breast cancer (MBC) is a cancer in males that originates in their breasts. Males account for less than 1% of new breast cancers with about 20,000 new cases being diagnosed worldwide every year. Its incidence rates in males vs. females are, respectively, 0.4 and 66.7 per 100,000 person-years. The worldwide incidences of male as well as female breast cancers have been increasing over the last few decades. Currently, one of every 800 men are estimated to develop this cancer during their lifetimes.
Howel–Evans syndrome is an extremely rare condition involving thickening of the skin in the palms of the hands and the soles of the feet (hyperkeratosis). This familial disease is associated with a high lifetime risk of esophageal cancer. For this reason, it is sometimes known as tylosis with oesophageal cancer (TOC).
A BRCA mutation is a mutation in either of the BRCA1 and BRCA2 genes, which are tumour suppressor genes. Hundreds of different types of mutations in these genes have been identified, some of which have been determined to be harmful, while others have no proven impact. Harmful mutations in these genes may produce a hereditary breast–ovarian cancer syndrome in affected persons. Only 5–10% of breast cancer cases in women are attributed to BRCA1 and BRCA2 mutations, but the impact on women with the gene mutation is more profound. Women with harmful mutations in either BRCA1 or BRCA2 have a risk of breast cancer that is about five times the normal risk, and a risk of ovarian cancer that is about ten to thirty times normal. The risk of breast and ovarian cancer is higher for women with a high-risk BRCA1 mutation than with a BRCA2 mutation. Having a high-risk mutation does not guarantee that the woman will develop any type of cancer, or imply that any cancer that appears was actually caused by the mutation, rather than some other factor.
Cancer is caused by genetic changes leading to uncontrolled cell growth and tumor formation. The basic cause of sporadic (non-familial) cancers is DNA damage and genomic instability. A minority of cancers are due to inherited genetic mutations. Most cancers are related to environmental, lifestyle, or behavioral exposures. Cancer is generally not contagious in humans, though it can be caused by oncoviruses and cancer bacteria. The term "environmental", as used by cancer researchers, refers to everything outside the body that interacts with humans. The environment is not limited to the biophysical environment, but also includes lifestyle and behavioral factors.
A hereditary cancer syndrome is a genetic disorder in which inherited genetic mutations in one or more genes predispose the affected individuals to the development of cancer and may also cause early onset of these cancers. Hereditary cancer syndromes often show not only a high lifetime risk of developing cancer, but also the development of multiple independent primary tumors.
Hereditary lobular breast cancer is a rare inherited cancer predisposition associated with pathogenic CDH1 (gene) germline mutations, and without apparent correlation with the hereditary diffuse gastric cancer syndrome. Research studies identified novel CDH1 germline variants in women with diagnosed lobular breast cancer and without any family history of gastric carcinoma. Firstly, in 2018 Giovanni Corso et al. defined this syndrome as a new cancer predisposition and the Authors suggested additional clinical criteria to testing CDH1 in lobular breast cancer patients. In 2020, the International Gastric Cancer Linkage Consortium recognized officially that the hereditary lobular breast cancer is a novel and independent syndrome. To date, there are reported about 40 families clustering for lobular breast cancer and associated with CDH1 germline mutations but without association with diffuse gastric cancer.