DLA6, DLA7- Molecular Pathology Flashcards Preview

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Flashcards in DLA6, DLA7- Molecular Pathology Deck (20):

Hereditary Hemochromatosis results from a mutation in the (1) gene and is inherited in (2) fashion. (T/F) hemochromatosis has 100% penetrance. The most common mutation with the highest risk with presence of two alleles is (4).

1- HFE
2- autosomal recessive
3- F, <100% penetrance
4- C282Y (90%)


explain Hereditary Hemochromatosis testing through traditional PCR

(about 3 hrs)
-amplification of DNA: cyles of denature (95C), anneal (68C), elongate (72C)
-add series of Restriction Endonucleases --> DNA lengths vary depending on RFLP (restriction fragment length polymorphism)
-fragments are run on Gel Electrophoresis --> separate by size
-under UV light, compare to standard


explain Hereditary Hemochromatosis testing through Real-time PCR

(about 20 mins)
-in the presence of a specific primer used to investigate a single base position --> add Nucleotides complementary to mutant and wild-type bases, label with fluorophores
-at different melting temperatures (varies based on mutation) measure fluorescence of both signals to determine homogeneity of either, or heterogeneity


list some inherited diseases that can be diagnosed by DNA based techniques

fragile X syndrome, CF, sickle cell, hemophilia, Huntington's, Neurofibromatosis, Factor V Leiden


BRCA1 genes is found on (1)

BRCA2 gene is found on (2)

1- chr.17, long arm (q) [band 17q21]
2- chr.13, long arm (q) [band 13q12.3]


list the two ways to test for BRCA mutations and why they are used

1- automated Sanger sequencing
2- Next Generation Sequencing (NGS)

-there is >200 mutation types for both BRCA genes, therefore it is pointless to use PCR to search for individual mutations since there isn't any common ones


compare Sanger and Next Gen. sequencing

-Sanger: use normal dNTPs and ddNTPs (dideoxyribonucleic acids) to stop simultaneous transcriptions at every base pair, sequence based on length (Gel electro.)
-NGS: template DNA mounted to slides, add florescent dNTPs, wash away the unbounded, sequenced by fluorescent machine


list some tumor susceptibility genes that patients can be screened for

-BRCA1, BRCA2 = breast/ovarian cancer
-RET = MEN syndrome
-P53 = Li Fraumeni syndrome
-APC = adenomatous polyposis


HNPCC, aka (1) or (2), is a diseased based on a mutation of (3) genes, most commonly the following: (4)

1- hereditary non-polyposis colon cancer
2- Lynch syndrome
3- DNA mismatch repair genes


list the traits or characterizations of HNPCC

(lynch syndrome)
-young age of Dx (colon cancer)
-synchronous and metasynchronous tumors in R colon
-tumor development in endometrium, ovary, stomach, small bowel, ureter, kidney
-presence of any of the above in 1st degree relatives


HNPCC is diagnosed by the presence of (1) in DNA, which are defined as (2). During testing for HNPCC, (3) is commonly tested for due to its prevalence in patients with colorectal cancer.

1/2- MSI (microsatellite instability)- repeated sequences of 1-6 NTs in length
3- BRAF mutation


Patients with HNPCC have a (1)% risk of developing colorectal and endometrial cancer. If mutations are discovered, surveillance includes (2) and (3). Additional surgical options include (4).

1- 80%
2- colonoscopy every 1-3 yrs, start at 20-25 y/o
3- transvaginal US, endometrial aspiration
4- colectomy with consideration for hysterectomy / salpingo-oophorectomy at same time


Besides BRCA mutations, (1) mutations are also common in breast cancer and indicate the (2) features on breast cancer prognosis. Testing is performed through either (3) or (4). Patients with overexpression of (1) are treated with (5).

1- HER2 (human epidermal growth receptor 2), overexpression
2- aggressive features and shorten disease-free survival
3- immunohistochemical staining
4- FISH (inc number of HER2 genes on chromosomes)
5- Trastuzumab (Herceptin)


FISH techiniques are useful in detecting malignancies including the following:....

-HER2 (breast cancer)
-Urothelial Carcinomas (aneuploidy, rearrangement, deletion, amplification of chromosomal DNA)
-Brain tumors due to oligodendrogliomas (50-80%) from 1p or 19q deletions


(1) oncogene mutations are common in colorectal cancer and other adenocarcinomas. Presence of (1) also prevents response to treatment that targets (2). (1) is detected by (3).

2- EGFR (anti-EGFR treatment)
3- DNA sequencing techniques (Sanger or NGS)


describe the 3 types of gene mutations seen in NSCLC

(non-small cell lung carcinomas: squamous cell carcinoma, adenocarcinoma)
-EGFR- treat with TKIs (tyrosine kinase inhibitors)
-ALK (anaplastic lymphoma kinase)- treat with ALK inhibitors, test through immunocytochemistry or FISH


40-60% of melanomas have a (1) mutation which leads to (2) activation. Most of these are a (3) specific mutation. Presence of (1) indicates (4) tumor prognosis. (1) is detected by (5).

1- BRAF mutation
2- MAP kinase activation
3- V600E
4- aggressive tumor
5- Real-Time PCR, Sequencing techniques (Sanger, NGS)


CML, aka (1), is due to (2) mutation occurring which results in (3) activation which drives (4) downstream. Diagnosis is detected by (5). Treatment is through (6).

1- chronic myeloid leukemia
2- chimeric BCR-ABL gene fusion
3- constitutive BCR-ABL TK activation
4- GF indep. proliferation (w/ complete differentiation) of myeloid progenitors => inc platelets and granulocytes
5- double FISH (translocation)
6- Imatinib (TK inhibitor)


____ is a great technique for testing infectious diseases

PCR- viral and bacterial assays completed (track infectious outbreaks)


identity determination techniques (ex. paternal testing) mainly includes....

1) VNTRs (variable number tandem repeats): 20-20000 nts long, considered DNA fingerprinting
2) STRs (short tandem repeats): multiple tetranucleotide repeats, PCR amplification
3) mitochondrial DNA (maternal testing)