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Flashcards in Biomarkers Deck (29):
1

What is MGMT (methylguanine-DNA-methyltransferase)?

Is a protein that repairs error in DNA.
When the gene encoding MGMT is silenced by methylation, chemotherapy may be more effective because cancer cells cannot repair cellular damage

2

What are the advantages of testing for MGMT (methylguanine-DNA-methyltransferase)?

It can identify if a patient could benefit from the chemotherapy drug temozolomide.

3

What tumor types may have an alteration in MGMT (methylguanine-DNA-methyltransferase)?

Anaplastic astrocytoma
Anaplastic oligodendroglia
Anaplastic oligoastrocytoma
Glioblastoma
Anaplastic gliomas

4

What is IDH1/IDH2?

Metabolic enzymes that help to produce energy for cells and have now been found to be mutated in additional cancers.

5

What are the advantages of testing for IDH1/IDH2?

Is performed as part of diagnostic workup for many brain tumors. IDH1/2 mutations can help confirm that a lesion is a tumor and no an inflammatory process. Help determine prognosis.

6

What tumor types may have an alteration in IDH1/2?

Occur mainly in low grade gliomas

7

What is 1p/19q?

The p-arm of chromosome 1 and the q-arm of chromosome 19 are found in all cells, but frequently missing in oligodendrogliomas due to a deletion mutation

8

What are the advantages of testing for 1p/19q?

the test looks at genetic changes to chromosome # 1 & 19. in tumor cells and whether these chromosomes are complete or have a section missing, research shows this could mean better outcomes for people.

9

What tumor types may have an alteration in 1p/19q?

Oligodendroglioma
Anaplastic oligodendroglioma
Oligoastrocytoma
Anaplastic oligoastrocytoma

10

What is BRAF?

BRAF is a gene that makes a protein called B-raf. B-raf sends signals to help direct the growth of cells within our body. It is part of the MAP kinase pathway, a longstanding cancer target. BRAF mutations are activating mutations, turning the gene on and enabling extra growth of cells

11

What are the advantages of testing for BRAF?

Brain tumors may have a fault with their BRAF gene. The V600E mutation in BRAF is a target of several drugs developed for treatment of melanoma. (Vemurafenib)

12

What tumor types may have an alteration in BRAF?

Only clinically useful in a few tumor types. Is most commonly used to determine whether a tumor is pilocytic astrocytoma. Typically BRAF mutation is limited to pediatric gliomas.

13

What is EGFR- epidermal growth factor receptor?

Is a member of the epidermal growth factor family and key cell signaling protein that is crucial for tumor growth. EGFR is thought to play a role in how GBM tumor develops, continues to grow, and spread, and its resistance to therapy.

14

What are the advantages of testing EGFR?

In glioma cells the EGFR is amplified so that the cancer cells have many additional copies of this important growth factor. EGFR testing can determine the number of copies that exist in glioma cells.

15

What tumor types may have an alteration in EGFR?

GBM

16

What are the advantages of testing EGFRvIII?

EGFRvIII mutation turns on EGFR growth factor signaling when it would otherwise be turned off.

17

What tumor types may have an alteration in EGFR?

GBM

18

What is PTEN?

PTEN gene codes for PTEN protein,
A known tumor suppressor genes
It is mutated in a large number of different cancers.

19

What are the advantages of testing PTEN?

PTEN is frequently mutated in glioblastoma. May be a sign that grade II/III astrocytomas tumors are progressing

20

What tumor types may have an alteration in PTEN?

GBM
Astrocytoma

21

What is TERT?

TERT gene encodes telomerase, and enzyme that produces protective caps at the ends of chromosomes. These caps are called telomerase, and they shorten as cells age, eventually causing cell death.

22

What are the advantages of testing TERT?

The mutations turn on the TERT gene, enabling cancer cells to keep their telomeres long. this allows glioma cells to divide indefinitely without aging and dying.

23

What tumor types may have an alteration in TERT?

found in 80% of glioblastomas and oligodendrogliomas, 25% of grade II/III astrocytomas.

24

What is ATRX?

ATRX alters DNA conformation in order to regulate which gene are expressed and which are silenced.

25

What are the advantages of testing ATRX?

ATRX are observed in 80% of grade II/III astrocytomas.
Commonly co-occurs with IDH mutation.
May have prognostic importance but unknown due to it occurring with IDH mutations.

26

What is Akt3?

Protein that is highly active in glioblastoma and which interacts with the additional glioma.

27

What tumor types may have alterations in Akt3

GBM

28

What is EGFRvIII?

Is a mutated form of EGFR. It has been found in about 30% of GBM.

29

What are the advantages of testing Akt3?

Akt3 presence may indicate a resistance to standard treatment.