Cancer Genetics Flashcards
sarcoma
cancers that form in the bones and soft tissues (can include muscles, bone, tendons, ligaments, lymph and blood vessels)
leukemia
cancer that begins in the blood forming tissue of the bone marrow
lymphoma
cancer that begins in the lymphocytes (usually B or T cells)
multiple myeloma
cancer that begins in plasma cells, which are immune cells; when abnormal versions of these cells build up in the marrow tumors can form throughout the body
melanoma
cancer that begins in cells that make pigment
-can occur in skin or eye
gliomas
benign tumors derived from cells of brain; pressure and size can cause problems
glioblastomas
malignant cell growth of the glioma
meningioma
- fairly common
- cancer of the meninges
astrocytoma
malignant cells derived from astrocytes
carcinoma
cancers derived from epithelial cells
germ cell tumors
tumors that arise from reproductive cells
neuroendocrine tumors (NETs)
formation of these can lead to complications related to hormone release
- most common in intestine, lung, panc, adrenal gland
- ex: pheos and paragangliomas (pheos not on adrenal gland), islet cell cancers
- can be benign or malignant
- can increase BP, sweating, anxiety
Carcinoids
Slow growing tumors often in GI; secrete substances like prostaglandins or serotonin and cause namesake syndrome
Tumor-specifics suggestive of hereditary cancer
Tumors in lateral organs or two different tumor types/primaries in the same organ
HER2+
somatic amplification is associated with poorer prognosis, but also a druggable target
atypia and breast cancer risk
- 20-25% risk in absence of family history of breast ca
- up to 40% cumulative risk with family history
DCIS
-non-invasive neoplasm of ductal origin
+currently treated, but controversial
+30% risk of becoming invasive cancer
-comedo type with higher risk of becoming invasive
LCIS
-not a pre-malignant breast cancer risk, but a marker of risk
-25-30% chance to become invasive
+often times b/l, multifocal and can invade ducts, so different place than cells are found becomes cancerous
+tx can include chemo or prophylactic mastectomy
BrCa risk factors
- aging
- early menstruation (<12y)
- late menopause (>52y)
- breast density
- nulliparity or first child later than 30y
- estrogen or progesterone use after menopause
- more than 2-3 alcoholic beverages per week
protective BrCa factors
- 4 or more hours of exercise per week
- maintaining ideal body weight to reduce body fat stores (especially after menopause)
- breastfeeding
- having children prior to 30y
ovarian cancer cells
arise from mullerian epithelium
-fallopian tube cancer and primary peritoneal cancer treated the same
sertoli-leydig cell cancer
- subset of sex-cord tumors
- occur in DICER1 and Peutz-Jehger
high grade serous tumors
associated with germline and somatic BRCA1/2 and TP53 mutations
ovarian cancer of low malignant potential
- “borderline”
- 15% of ovarian tumors
- less associated with BRCA1/2
ovarian cancer risk factors
- age
- post-menopausal HRT
- infertility
- nulliparity
- endometriosis
- increased cycles
ovarian cancer risk reduction
- OCPs
- tubal ligation
- TAH-BSO
- breast feeding
- multiple births
serous tubal intraepithelial carcinoma (STIC)
- precursor lesion, as we know high grade serous carcinomas can begin in FTs
- studies for BS with delayed oophorectomy in risk reduction
Gail Model
-breast cancer risk assessment model
+absolute lifetime risk until 90y
+5y risk
-historically used to determine chemoprevention eligibility
Gail assessment factors
- age
- 1st live birth age, menarche age
- number of first degree female relatives with breast cancer
- number of breast bx and presence of hyperplasias
- race
Gail limitations
- only incorporates breast cancer diangoses
- only uses up to second degree relatives
- paternal history excluded
- age of diagnoses excluded
Claus tables
- statistical model used to calculate breast cancer risk
- stratified by age of diagnosis in relatives and age of patient
prior probability models
-determine risk to test mutation positive (mostly BRCA1/2)
-can be useful for determining who is a research v. clincal testing candidate
+many programs consider 5-10% enough risk
cancer gene connect
can evaluate PP for many cancer types
Penn II model
calculates PP for BRCA1/2 mutations
BOADICEA
cancer risk assessment and PP for several cancers
Tyrer-Cuzick
uses family history info and “epidemiological” risk factors to calculate BrCa risk and BRCA1/2 PP
HBOC cancers
br, ov, panc, prostate, melanoma
LFS cancers
br, brain, adrenocortical (ACC), sarcoma or osteosarcoma at 45 or under, leukemia, choroid plexus tumors in childhood
Cowden cancers
breast (25-50% in 30s-40s), thyroid (mainly follicular, 10% risk), trichilemommas, papillomatous papule, uterine (5-10%), kidney
PALB2 cancers
br, panc, ov-unconfirmed
HDGC cancers
lobular breast, diffuse gastric
Peutz-Jegher ca
-br, panc, colon, gastric, hamartomous polyps, mucocutaneous lesions, lung
HBOC genetics
-mutations of BRCA1/2
+effects homologous recombination DNA repair, cell cycle checkpoint control, proteolytic ubiquitylation, transcriptional regulation-DNA damage is a key activator of normal activity
-incidence of 1 in 40 in AJ pop
-incidence of 1 in 300 among Caucasian, AA, and Asian populations
PARP inhibitors
target additional enzyme in BER, causing cell already missing repair mechanism to die
-other cells with deficiencies in FA/homologous recombination repair pathway may be candidates for therapy (ex: triple negative and somatic cancers)
pancreatitis-like changes in BRCA2
pancreatitis can generally be due to infections, etc, causing inflammation
-study using endoscopic u/s found people with mutations had increased lesions, cysts and pancreatitis
FANC genes
-FANCA, FANCC, FANCG mutations account 80-90% of disease
+note: BRCA2=FANCD1
-bi-allelic PALB2/FANCN, BRIP1/FANCJ and RAD51C can also cause FA
-FANCB XL, RAD51 AD
-most patients are compound heterozygotes
-mutation of genes mostly affects the ability of the core complex to activate correction of inter-strand cross links
AJ HBOC Founder Mutations
-BRCA1 \+187delAG \+5385inC -BRCA2 \+6174delT
BRCA positive screening management
-biannual CBE, SBE and annual BrMRI at 25y
-annual mammo at 30y
+consideration of staggered MRI, mammo
-CA125 and transvaginal u/s at least 1x/yr; no proof of effectiveness of this
BRCA positive surgical management
-risk reducing or prophylactic mastectomy
+decreases BrCa risk by 90%
-risk reducing or prophylactic oophorectomy after child bearing (35-40y-BRCA1, 40-45y-BRCA2)
+TAH-BSO consideration
chemoprevention in BRCA
- tamoxifen-positive premenopausal women
- raloxifene-tamoxifen without increased uterine cancer risk
- aromatase inhibitors-only for use in post-menopausal women
LFS genetics
- mutation of TP53
- increases risk for cancer to 50% by age 35y; lifetime risk 90% for women, 70% for men
- 7-20% de novo mutation risk
- increased risk for 2nd primaries and radiation-induced tumors
sarcomas in LFS
especially concerning for female carriers in radiation field-reason to consider mastectomy over lumpectomy
LFS management
- biannual CBE by 20y or 5-10y before earliest onset in family
- annual brMRI with or w/out mammo by 20-25y; switches to both alternating 30-75y
- consideration of risk reducing mastectomy
- comprehensive PE, blood counts, neuro and skin exams
- colonoscopy every 2-3y at least by 25y
- additional surveillance based on family history with considerations of brain MRI, rapid full body MRI and u/s
hamartoma
growth of normal tissue in a place it should not
PTEN features
- cancers
- macrocephaly with or without ASD
- skin findings: trichilemmomas and papillomatous papules by late 20s near lips, nose, mouth and eyes, lipomas, fibromas
- benign brain tumors-cerebellar dysplastic gangliocytoma in LDD that can present as hydrocephalus
- esophageal glycogenic acanthosis
clinical Cowden criteria
- molecular mutation of PTEN
- 3+ major criteria one of which must be macrocephaly; can include LDD, GI hamartomas
- or 2 major and 3+ minor criteria
Cowden management
- biannual CBE by 25y or 5-10y before earliest onset
- annual mammo and MRI by 25y
- consideration of mastectomy and hysterectomy
- comprehensive PE with focus on thyroid starting and a thyroid u/s by 18y
- colonoscopy starting at 35y every 5-10y and increased frequency for polyps or symptoms
- consider annual derm exam
Bannayan-Riley-Ruvacalba
PTEN syndrome with macrocephaly, hamartomous intestinal polyposis, pigmented macules of the glans penis
Proteus syndrome
PTEN syndrome with connective tissue nevi, disproportionate overgrowth (skull, limbs, hands, feet, vertebrae, etc), lipomas or absence of fat, vascular malformation, facial phenotype (long face, low nasal bridge, down slanting palpebral fissures, wide nostrils, open mouth expression)
standard colonic resection
- removal of tumor and portion of surrounding colon
- may be more common in non-hereditary syndrome carriers
CRC risk factors
- aging
- personal history of cancer or adenomas (polyps)
- inflammatory bowel disease (Chron’s, ulcerative colitis)
- family history and/or hereditary syndrome predisposition
- smoking and alcohol
- obesity
adenomatous polyps
associated with an increased risk to develop colon cancer; pre-malignant & typically calls for increased colonoscopy
hyperplastic polyps
more concerning if of mixed pathology, alone not considered pre-malignant
hamartomatous polyps
- tissue growing where it is not meant to in the colon
- can have very specific features
peutz-jegher polyps
type of hamartomatous polyp, has a frond-like or broccoli stalk appearance (<100)
- small intestinal/jejunal more common, though can see respiratory or urinary tract polyps, sometimes adenomatous polyps
- can require several surgeries due to obstruction, intussusception, abdominal pain, and GI pain <20y in 50% patients
sessile serrated polyps
behave like adenomatous polyps, in one syndrome development someone can develop 20+; can have mixed pathology suggestive of further genetic invesigation
FAP genetics
-AD mutations in APC (5q) \+mostly lead to truncations -30% cases de novo, many mutations also private -genotype-phenotype correlations occur *not all mutations detectable yet
attenuated FAP
- usually caused by mutations at the 5’ or 3’ end of APC
- later onset (CRC ~50y)
- fewer colonic polyps (20<100)
- common to have extracolonic features, except CHRPE
severe FAP
- causes hundreds or thousands of polyps
- seen with mutations in exon 15 of APC
desmoid tumors
-benign growths of connective tissues
+cannot typically be removed surgically as they will return
-due to centrally located mutations in exon 15 of APC-so more common in severe FAP
I1307K
- AJ APC mutation (6% pop) creates a hypermutable region
- associated with a slight increase in colon cancer risk, not polyposis
- consideration of colonoscopies every 5y starting at 40