Hepatoblastoma | |
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Micrograph of a hepatoblastoma. H&E stain. | |
Specialty | Oncology |
Hepatoblastoma is a malignant liver cancer occurring in infants and children and composed of tissue resembling fetal liver cells, mature liver cells, or bile duct cells. They usually present with an abdominal mass. The disease is most commonly diagnosed during a child's first three years of life. [1] Alpha-fetoprotein (AFP) levels are commonly elevated, but when AFP is not elevated at diagnosis the prognosis is poor. [2]
Patients are usually asymptomatic at diagnosis. [3] As a result, disease is often advanced at diagnosis.
Hepatoblastomas originate from immature liver precursor cells, are typically unifocal, affect the right lobe of the liver more often than the left lobe, and can metastasize. They are categorized into two types: "Epithelial Type" and "Mixed Epithelial / Mesenchymal Type."[ citation needed ]
Individuals with familial adenomatous polyposis (FAP), a syndrome of early-onset colonic polyps and adenocarcinoma, frequently develop hepatoblastomas. [5] [6] Also, beta-catenin mutations have been shown to be common in sporadic hepatoblastomas, occurring in as many as 67% of patients. [7] [8]
Recently, other components of the Wnt signaling pathway have also demonstrated a likely role in constitutive activation of this pathway in the causation of hepatoblastoma. [8] [9] Accumulating evidence suggests that hepatoblastoma is derived from a pluripotent stem cell. [10]
Syndromes with an increased incidence of hepatoblastoma include Beckwith–Wiedemann syndrome, trisomy 18, trisomy 21, Acardi syndrome, Li–Fraumeni syndrome, Goldenhar syndrome, von Gierke disease, and familial adenomatous polyposis. [11]
The most common method of testing for hepatoblastoma is a blood test checking the alpha-fetoprotein level. Alpha-fetoprotein (AFP) is used as a biomarker to help determine the presence of liver cancer in children. At birth, infants have relatively high levels of AFP, which fall to normal adult levels by the second year of life. The normal level for AFP in children has been reported as lower than 50 nanograms per milliliter (ng/ml) and 10 ng/ml in adults. An AFP level greater than 500 ng/ml is a significant indicator of hepatoblastoma. AFP is also used as an indicator of treatment success. If treatments are successful in removing the cancer, the AFP level is expected to return to normal. [12]
Surgical removal of the tumor, neoadjuvant chemotherapy prior to tumor removal, and liver transplantation have been used to treat these cancers. [13] [14] Primary liver transplantation provides high, long term, disease-free survival rate in the range of 80%, in cases of complete tumor removal and adjuvant chemotherapy survival rates approach 100%. [15] [16] The presence of metastases is the strongest predictor of a poor prognosis. [17]
Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer in adults and is currently the most common cause of death in people with cirrhosis. HCC is the third leading cause of cancer-related deaths worldwide.
Alpha-fetoprotein is a protein that in humans is encoded by the AFP gene. The AFP gene is located on the q arm of chromosome 4 (4q13.3). Maternal AFP serum level is used to screen for Down syndrome, neural tube defects, and other chromosomal abnormalities.
Beckwith–Wiedemann syndrome is an overgrowth disorder usually present at birth, characterized by an increased risk of childhood cancer and certain congenital features. A minority (<15%) of cases of BWS are familial, meaning that a close relative may also have BWS, and parents of an affected child may be at increased risk of having other children with BWS. While children with BWS are at increased risk of childhood cancer, most children with BWS do not develop cancer and the vast majority of children who do develop cancer can be treated successfully.
Gardner's syndrome is a subtype of familial adenomatous polyposis (FAP). Gardner syndrome is an autosomal dominant form of polyposis characterized by the presence of multiple polyps in the colon together with tumors outside the colon. The extracolonic tumors may include osteomas of the skull, thyroid cancer, epidermoid cysts, fibromas, as well as the occurrence of desmoid tumors in approximately 15% of affected individuals.
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 benign tumor is a mass of cells (tumor) that does not invade neighboring tissue or metastasize. Compared to malignant (cancerous) tumors, benign tumors generally have a slower growth rate. Benign tumors have relatively well differentiated cells. They are often surrounded by an outer surface or stay contained within the epithelium. Common examples of benign tumors include moles and uterine fibroids.
Mismatch repair cancer syndrome (MMRCS) is a cancer syndrome associated with biallelic DNA mismatch repair mutations. It is also known as Turcot syndrome and by several other names.
A blastoma is a type of cancer, more common in children, that is caused by malignancies in precursor cells, often called blasts. Examples are nephroblastoma, medulloblastoma, and retinoblastoma. The suffix -blastoma is used to imply a tumor of primitive, incompletely differentiated cells, e.g., chondroblastoma is composed of cells resembling the precursor of chondrocytes.
In oncology, AFP-L3 is an isoform of alpha-fetoprotein (AFP), a substance typically used in the triple test during pregnancy and for screening chronic liver disease patients for hepatocellular carcinoma (HCC). AFP can be fractionated by affinity electrophoresis into three glycoforms: L1, L2, and L3 based on the reactivity with the lectin Lens culinaris agglutinin (LCA). AFP-L3 binds strongly to LCA via an additional α 1-6 fucose residue attached at the reducing terminus of N-acetylglucosamine; this is in contrast to the L1 isoform. It is the L1 isoform which is typically associated with non-HCC inflammation of liver disease condition. The L3 isoform is specific to malignant tumors and its detected presence can serve to identify patients whom need increased monitoring for the development of HCC in high risk populations. AFP-L3% is now being considered as a tumor marker for the North American demographic.
Adenomatous polyposis coli (APC) also known as deleted in polyposis 2.5 (DP2.5) is a protein that in humans is encoded by the APC gene. The APC protein is a negative regulator that controls beta-catenin concentrations and interacts with E-cadherin, which are involved in cell adhesion. Mutations in the APC gene may result in colorectal cancer and desmoid tumors.
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.
Aggressive fibromatosis or desmoid tumor is a rare condition. Desmoid tumors are a type of fibromatosis and related to sarcoma, though without the ability to spread throughout the body (metastasize). The tumors arise from cells called fibroblasts, which are found throughout the body and provide structural support, protection to the vital organs, and play a critical role in wound healing. These tumors tend to occur in women in their thirties, but can occur in anyone at any age. They can be either relatively slow-growing or malignant. However, aggressive fibromatosis is locally aggressive and can cause life-threatening problems or even death when the tumors compress vital organs such as intestines, kidneys, lungs, blood vessels, or nerves. The condition is rarely fatal. Most cases are sporadic, but some are associated with familial adenomatous polyposis (FAP). Approximately 10% of individuals with Gardner's syndrome, a type of FAP with extracolonic features, have desmoid tumors.
Catenin beta-1, also known as β-catenin (beta-catenin), is a protein that in humans is encoded by the CTNNB1 gene.
Mediastinal germ cell tumors are tumors that derive from germ cell rest remnants in the mediastinum. Germ cell tumors most commonly occur in the gonad but occasionally elsewhere.
Liver cancer, also known as hepatic cancer, primary hepatic cancer, or primary hepatic malignancy, is cancer that starts in the liver. Liver cancer can be primary in which the cancer starts in the liver, or it can be liver metastasis, or secondary, in which the cancer spreads from elsewhere in the body to the liver. Liver metastasis is the more common of the two liver cancers. Instances of liver cancer are increasing globally.
Beta-catenin-interacting protein 1 is a protein that is encoded in humans by the CTNNBIP1 gene.
Axin-1 is a protein that in humans is encoded by the AXIN1 gene.
Elevated alpha-fetoprotein refers to a state where alpha-fetoprotein levels are outside of the reference range.
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.
Gardner fibroma (GF) is a benign fibroblastic tumor. GF tumors typically develop in the dermis and adjacent subcutaneous tissue lying just below the dermis. These tumors typically occur on the back, abdomen, and other superficial sites but in rare cases have been diagnoses in internal sites such as the retroperitoneum and around the large blood vessels in the upper thoracic cavity. The World Health Organization, 2020, classified Gardner fibroma as a benign tumor in the category of fibroblastic and myofibroblastic tumors.
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