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Thyroid Tumors, PIK3CA, E545G (c.1634A>G)

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Expand Collapse Thyroid Tumor  - General Description This year about 56,000 people in the U.S. (77% of them women) will be told by a doctor that they have thyroid cancer. About half of these new patients will be at least 50 years old. However, more than 500,000 patients with thyroid cancer remain alive today.

The thyroid is a butterfly-shaped gland found at the base of the throat, near the windpipe (trachea). The 2 wings (lobes) of the thyroid are connected by a thin piece of tissue called the isthmus. The thyroid uses iodine from food and iodized salts to make hormones that control the heart rate, body temperature, the speed with which food is changed into energy (metabolism) and the level of calcium in the blood. Based on their appearance under the microscope, the 4 main types of thyroid cancer are papillary, follicular, medullary and anaplastic. For treatment purposes, thyroid cancers are often classified as differentiated (papillary or follicular) or poorly differentiated (medullary or anaplastic). If a cancer cell is well-differentiated, it has most of the characteristics of a normal cell. On the other hand, poorly differentiated cancer cells don't look like normal cells.

Follicular thyroid cancer is a slow-growing cancer that forms in follicular cells, which are epithelial cells that take up iodine and make certain thyroid hormones. Papillary thyroid cancer, which appears as finger-like shapes under the microscope, also begins in follicular cells and is slow-growing. It is the most common type of thyroid cancer, usually appearing before the age of 45 years. It is more common in women than in men. Medullary thyroid cancer accounts for about 4% of all thyroid cancers. It begins in C cells, which make calcitonin, a hormone that helps keep calcium at the right level in the blood. Anaplastic thyroid cancer is a rare, aggressive form of cancer whose cells don't look at all like normal thyroid cells.

Thyroid cancer (and other tumors) can spread (metastasize) from the place where it started (the primary tumor) in 3 ways. First, it can invade the normal tissue surrounding it. Second, cancer cells can enter the lymph system and travel through lymph vessels to distant parts of the body. Third, the cancer cells can get into the bloodstream and go to other places in the body. In these distant places, the cancer cells cause secondary tumors to grow. The main places to which thyroid cancer spreads are the lungs, liver, and bones.

To find out whether the cancer has entered the lymph system, a surgeon removes all or part of a node near the primary tumor and a pathologist looks at it through a microscope to see if cancer cells are present. Several kinds of imaging can also be performed to determine if the cancer has spread. These include chest x-rays, ultrasound and CT scans.

The FDA has approved the targeted therapy vandetanib (Capreisa) for treatment of medullary thyroid cancer that is locally advanced and can't be removed by surgery or that has metastasized. No targeted therapies are yet available for treatment of anaplastic thyroid cancer. Therefore, novel therapies and treatment strategies are needed.

Source: National Cancer Institute, 2012
Thyroid cancer represents approximately 3% of new malignancies occurring annually in the United States, with an estimated 56,460 cancer diagnoses and 1,780 cancer deaths per year. Of these cancer diagnoses, 2% to 3% are medullary thyroid cancer (MTC).

MTC arises from the calcitonin-secreting parafollicular cells of the thyroid gland. MTC occurs in sporadic and familial forms and may be preceded by C-cell hyperplasia (CCH), although CCH is a relatively common abnormality in middle-aged adults.

Average survival for MTC is lower than that for more common thyroid cancers (e.g., 83% 5-year survival for MTC compared with 90-94% 5-year survival for papillary and follicular thyroid cancer). Survival is correlated with stage at diagnosis. Decreased survival in MTC can be accounted for, in part, by a high proportion of late-stage diagnoses.

In addition to early stage at diagnosis, other factors associated with improved survival in MTC include smaller tumor size, younger age at diagnosis, familial versus sporadic form and diagnosis by biochemical screening (i.e., screening for calcitonin elevation).

A Surveillance, Epidemiology, and End Results (SEER) population-based study of 1,252 MTC patients found that survival varied by extent of local disease. For example, the 10-year survival rates ranged from 95% for disease confined to the thyroid gland to 40% for those with distant metastases.

While the majority of MTC cases are sporadic, approximately 20-25% are hereditary because of mutations in the RET proto-oncogene. Mutations in the RET gene cause multiple endocrine neoplasia type 2 (MEN 2), an autosomal dominant disorder associated with a high lifetime risk of MTC. Multiple endocrine neoplasia type 1 (MEN 1) is an autosomal dominant endocrinopathy that is genetically and clinically distinct from MEN 2. However, the similar nomenclature for MEN 1 and MEN 2 may cause confusion. Of note, there is no increased risk of thyroid cancer for MEN 1.

Historically, MEN 2 has been classified into three subtypes based on the presence or absence of certain endocrine tumors in the individual or family:

- MEN 2A
- Familial medullary thyroid carcinoma (FMTC)
- MEN 2B

All three subtypes impart a high risk of developing MTC. MEN 2A has an increased risk of pheochromocytoma and parathyroid adenoma and/or hyperplasia. MEN 2B has an increased risk of pheochromocytoma and includes additional clinical features such as mucosal neuromas of the lips and tongue, distinctive faces with enlarged lips, ganglioneuromatosis of the gastrointestinal tract and an asthenic Marfanoid body habitus. FMTC has been defined as the presence of at least four individuals with MTC without any other signs or symptoms of pheochromocytoma or hyperparathyroidism in the proband or other family members.

Some families previously classified as FMTC will go on to develop one or more of the MEN 2A-related tumors, suggesting that FMTC is simply a milder variant of MEN 2A. Offspring of affected individuals have a 50% chance of inheriting the gene mutation.

The age of onset of MTC varies in different subtypes of MEN 2. MTC typically occurs in early childhood for MEN 2B, predominantly early adulthood for MEN 2A and middle age for FMTC.

DNA-based germline testing of the RET gene (chromosomal region 10q11.2) identifies disease-causing mutations in more than 95% of individuals with MEN 2A and MEN 2B and in about 88% of individuals with FMTC.

Source: National Cancer Institute, 2012
This year about 56,000 people in the U.S. (77% of them women) will be told by a doctor that they have thyroid cancer. About half of these new patients will be at least 50 years old. However, more than 500,000 patients with thyroid cancer remain alive today.

The thyroid is a butterfly-shaped gland found at the base of the throat, near the windpipe (trachea). The 2 wings (lobes) of the thyroid are connected by a thin piece of tissue called the isthmus. The thyroid uses iodine from food and iodized salts to make hormones that control the heart rate, body temperature, the speed with which food is changed into energy (metabolism) and the level of calcium in the blood. Based on their appearance under the microscope, the 4 main types of thyroid cancer are papillary, follicular, medullary and anaplastic. For treatment purposes, thyroid cancers are often classified as differentiated (papillary or follicular) or poorly differentiated (medullary or anaplastic). If a cancer cell is well-differentiated, it has most of the characteristics of a normal cell. On the other hand, poorly differentiated cancer cells don't look like normal cells.

Follicular thyroid cancer is a slow-growing cancer that forms in follicular cells, which are epithelial cells that take up iodine and make certain thyroid hormones. Papillary thyroid cancer, which appears as finger-like shapes under the microscope, also begins in follicular cells and is slow-growing. It is the most common type of thyroid cancer, usually appearing before the age of 45 years. It is more common in women than in men. Medullary thyroid cancer accounts for about 4% of all thyroid cancers. It begins in C cells, which make calcitonin, a hormone that helps keep calcium at the right level in the blood. Anaplastic thyroid cancer is a rare, aggressive form of cancer whose cells don't look at all like normal thyroid cells.

Thyroid cancer (and other tumors) can spread (metastasize) from the place where it started (the primary tumor) in 3 ways. First, it can invade the normal tissue surrounding it. Second, cancer cells can enter the lymph system and travel through lymph vessels to distant parts of the body. Third, the cancer cells can get into the bloodstream and go to other places in the body. In these distant places, the cancer cells cause secondary tumors to grow. The main places to which thyroid cancer spreads are the lungs, liver, and bones.

To find out whether the cancer has entered the lymph system, a surgeon removes all or part of a node near the primary tumor and a pathologist looks at it through a microscope to see if cancer cells are present. Several kinds of imaging can also be performed to determine if the cancer has spread. These include chest x-rays, ultrasound and CT scans.

The FDA has approved the targeted therapy vandetanib (Capreisa) for treatment of medullary thyroid cancer that is locally advanced and can't be removed by surgery or that has metastasized. No targeted therapies are yet available for treatment of anaplastic thyroid cancer. Therefore, novel therapies and treatment strategies are needed.

Source: National Cancer Institute, 2012
Thyroid cancer represents approximately 3% of new malignancies occurring annually in the United States, with an estimated 56,460 cancer diagnoses and 1,780 cancer deaths per year. Of these cancer diagnoses, 2% to 3% are medullary thyroid cancer (MTC).

MTC arises from the calcitonin-secreting parafollicular cells of the thyroid gland. MTC occurs in sporadic and familial forms and may be preceded by C-cell hyperplasia (CCH), although CCH is a relatively common abnormality in middle-aged adults.

Average survival for MTC is lower than that for more common thyroid cancers (e.g., 83% 5-year survival for MTC compared with 90-94% 5-year survival for papillary and follicular thyroid cancer). Survival is correlated with stage at diagnosis. Decreased survival in MTC can be accounted for, in part, by a high proportion of late-stage diagnoses.

In addition to early stage at diagnosis, other factors associated with improved survival in MTC include smaller tumor size, younger age at diagnosis, familial versus sporadic form and diagnosis by biochemical screening (i.e., screening for calcitonin elevation).

A Surveillance, Epidemiology, and End Results (SEER) population-based study of 1,252 MTC patients found that survival varied by extent of local disease. For example, the 10-year survival rates ranged from 95% for disease confined to the thyroid gland to 40% for those with distant metastases.

While the majority of MTC cases are sporadic, approximately 20-25% are hereditary because of mutations in the RET proto-oncogene. Mutations in the RET gene cause multiple endocrine neoplasia type 2 (MEN 2), an autosomal dominant disorder associated with a high lifetime risk of MTC. Multiple endocrine neoplasia type 1 (MEN 1) is an autosomal dominant endocrinopathy that is genetically and clinically distinct from MEN 2. However, the similar nomenclature for MEN 1 and MEN 2 may cause confusion. Of note, there is no increased risk of thyroid cancer for MEN 1.

Historically, MEN 2 has been classified into three subtypes based on the presence or absence of certain endocrine tumors in the individual or family:

- MEN 2A
- Familial medullary thyroid carcinoma (FMTC)
- MEN 2B

All three subtypes impart a high risk of developing MTC. MEN 2A has an increased risk of pheochromocytoma and parathyroid adenoma and/or hyperplasia. MEN 2B has an increased risk of pheochromocytoma and includes additional clinical features such as mucosal neuromas of the lips and tongue, distinctive faces with enlarged lips, ganglioneuromatosis of the gastrointestinal tract and an asthenic Marfanoid body habitus. FMTC has been defined as the presence of at least four individuals with MTC without any other signs or symptoms of pheochromocytoma or hyperparathyroidism in the proband or other family members.

Some families previously classified as FMTC will go on to develop one or more of the MEN 2A-related tumors, suggesting that FMTC is simply a milder variant of MEN 2A. Offspring of affected individuals have a 50% chance of inheriting the gene mutation.

The age of onset of MTC varies in different subtypes of MEN 2. MTC typically occurs in early childhood for MEN 2B, predominantly early adulthood for MEN 2A and middle age for FMTC.

DNA-based germline testing of the RET gene (chromosomal region 10q11.2) identifies disease-causing mutations in more than 95% of individuals with MEN 2A and MEN 2B and in about 88% of individuals with FMTC.

Source: National Cancer Institute, 2012
Expand Collapse PIK3CA  - General Description
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PIK3CA is a gene that provides the code for making one piece of the phosphatidylinositol 3-kinase (PI3K) protein, which is an enzyme that is part of an important signaling pathway (PI3K/AKT) involved in controlling the growth, division, survival, nutrient utilization, movement and structure of cells. PIK3CA encodes the catalytic subunit of PI3K, which is the part of the protein that lets it function as an enzyme. PI3K function is tightly maintained in normal cells. The enzymatic activity is activated by specific signals from growth factor receptor tyrosine kinases (RTKs) or from activated RAS proteins. PI3K then generates molecules that attract another enzyme (particularly AKT) to the cell membrane, where it is activated. The activated AKT acts on other proteins that regulate various cell processes that promotes cell growth and survival.

Mutations in PIK3CA lead to enhanced activation of its signaling function, thereby driving the tumorigenic process. These activating mutations are commonly associated with breast and colon cancer, and more rarely with melanoma of the skin. Defects in this gene have also been associated with ovarian cancer, endometrial cancer, and liver cancer.

Tumor mutation profiling performed clinically at the MGH Cancer Center has identified PIK3CA mutations across a broad-spectrum of cancer types. The highest incidence of PIK3CA mutations have been found in endometrial cancer (25%), breast cancer (20%), colon cancer (25%) and cancers of the head and neck (10%). In the other major tumor types, PIK3CA mutations have been found in less than 10% of cases that have been tested.

Sources: Genetics Home Reference
The PIK3CA gene encodes the p110 alpha catalytic subunit of the phosphoinositol 3-kinase (PI3K) complex. PI3K receives upstream activation signals from growth factor receptor tyrosine kinases (e.g. EGFR family members), and in turn signals through AKT and mTOR in order to promote cell survival, cell growth and cellular proliferation. PIK3CA mutations lead to increased activation of PI3K/AKT/mTOR signaling. PI3K function is opposed by PTEN, a lipid phosphatase that is often inactivated by mutations or silenced by methylation in many cancers.

Tumor mutation profiling performed clinically at the MGH Cancer Center has identified PIK3CA mutations across a broad-spectrum of cancer types. The highest incidence of PIK3CA mutations have been found in endometrial cancer (25%), breast cancer (20%), colon cancer (25%) and cancers of the head and neck (10%). In the other major tumor types, PIK3CA mutations have been found in less than 10% of cases that have been tested.

Sources: Genetics Home Reference
Expand Collapse E545G (c.1634A>G)  in PIK3CA
The PIK3CA E545G mutation arises from a single nucleotide change (c.1634A>G) and results in an amino acid substitution of the glutamic acid (E) at position 545 by a glycine (G).
The PIK3CA E545G mutation arises from a single nucleotide change (c.1634A>G) and results in an amino acid substitution of the glutamic acid (E) at position 545 by a glycine (G).

PIK3CA mutations have been reported in about 10% of follicular and anaplastic thyroid carcinomas. Preclinical laboratory studies have shown that PIK3CA-mutant cell lines and tumor models are more sensitive to PI3K pathway inhibitors (given either as a single-agent or in combination with other targeted therapies), when compared to PIK3CA non-mutated tumors (PIK3CA wild-type). Multiple clinical trials are currently underway to validate this hypothesis.

PIK3CA mutations have been reported in about 10% of follicular and anaplastic thyroid carcinomas. Preclinical laboratory studies have shown that PIK3CA-mutant cell lines and tumor models are more sensitive to PI3K pathway inhibitors (given either as a single-agent or in combination with other targeted therapies), when compared to PIK3CA non-mutated tumors (PIK3CA wild-type). Multiple clinical trials are currently underway to validate this hypothesis.

PubMed ID's
20578891

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Your Matched Clinical Trials

Trial Matches: (D) - Disease, (G) - Gene, (M) - Mutation
Trial Status: Showing all 2 results Per Page:
Protocol # Title Location Status Match
NCT00585195 A Study Of Oral PF-02341066, A c-Met/Hepatocyte Growth Factor Tyrosine Kinase Inhibitor, In Patients With Advanced Cancer A Study Of Oral PF-02341066, A c-Met/Hepatocyte Growth Factor Tyrosine Kinase Inhibitor, In Patients With Advanced Cancer MGH Open D
NCT02568267 Basket Study of Entrectinib (RXDX-101) for the Treatment of Patients With Solid Tumors Harboring NTRK 1/2/3 (Trk A/B/C), ROS1, or ALK Gene Rearrangements (Fusions) Basket Study of Entrectinib (RXDX-101) for the Treatment of Patients With Solid Tumors Harboring NTRK 1/2/3 (Trk A/B/C), ROS1, or ALK Gene Rearrangements (Fusions) MGH Open D
MGH has many open clinical trials for other cancers not shown on the Targeted Cancer Care website. They can be found on the MassGeneral.org clinical trials search page.

Additional clinical trials may be applicable to your search criteria, but they may not be available at MGH. These clinical trials can typically be found by searching the clinicaltrials.gov website.
Trial Status: Showing all 2 results Per Page:

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