Neoplasia Genes: Horrible Combinations of Letters and Numbers Flashcards
Follicular lymphoma characteristic genetic change
t(14;18) BCL2 fusion to IgH. BCL2 is overexpressed, and BCL2 inhibits BAX/BAK signals of the apoptotic pathway. So, apoptosis is inhibited.
Follicular lymphoma is low-grade, but frequently acquires mutations to become high grade -> diffuse large B cell lymphoma
Mantle Cell Lymphoma characteristic genetic change
t(11;14). BCL1 is on chromosome 11, and Ig heavy chain is on chromosome 14 (notice that many lymphomas involve translocations to chromosome 14 so that some oncogene becomes constitutionally active).
some extra shit: BCL1 codes cyclin D1. Cyclin D1 promotes G1/S transition.
MALT Lymphoma (less important to remember this genetic alteration):
t(11;18) MALT1/IAP2
Burkitt lymphoma characteristic genetic change
EBV or sporadic mutation -> t(8;14). Chromosome 8 has MYC gene. So, c-myc moves to Ig heavy chain locus and is overexpressed.
c-myc oncogene -> cell proliferation
Two oncogenes of EBV:
LMP1 (NFKB/JAK STAT pathway) that activates BCL2
EBNA2 upregulates cyclin D1
Diffuse Large B Cell Lymphoma characteristic genetic change
either sporadic or transformation from follicular lymphoma with t(14;18) with BCL2.
Frequently also have BCL6 mutation
Antigens on Reed-Sternberg Cell
CD15+ and CD30+, while also being CD45 negative
CLL antigens
CD5 and CD20 (these two are the most important, especially CD5 but that also shows up in Mantle cell Lymphoma. CD5 normally associated more with healthy T cells) + CD19, CD23
CML characteristic genetic change
t(9;22) BCR-ABL fusion. Tyrosine kinase -> proliferation.
PMF, PV, ET characteristic genetic change
V617F JAK2 tyrosine kinase -> proliferation
Acute Promyelocytic Leukemia characteristic genetic change
t(15;17) PML/RAR alpha fusion. This type is also called M3 in the old classification (FAB: French-American-British. AMLs were ordered M1-M7)
Low-risk HPV serotypes:
1, 2, 4, 7
there are a lot more but not mentioned by Matolcsy
High risk HPV serotypes
16, 18, 31
High risk HPV neoplasia-related exons:
E6 blocks p53, BAX, and telomerase. E7 blocks RB.
4 oncogene mutations to know
- Point mutations: EGFR tyrosine kinase mutations cause uncontrolled proliferation
- Promoter exchange translocations: t(14;18) BCL2 - Follicular Lymphoma
- Fusion Gene translocation: t(9;22) CML ALL, Philadelphia chromosome
- Gene Amplification: HER2/Neu (a type of EGFR)
5 mechanisms for tumor suppressor gene inactivation
- Stop codon or missense mutation
- Epigenetics
- Transdominant genes
- Haploinsufficiency
Can cause loss of heterozygosity in people who inherit one mutant allele
3 Tumor suppressor genes to know and their normal roles
- RB: normally binds E2F, preventing E2F from starting S phase until Cyclin D + CDK4/6 phosphorylates RB
- p53 normally binds MDM2 and is degraded, until the cell is stressed. It then tries to repair DNA, make the cell silent, or undergo apoptosis
- APC: normally binds beta catenin and prevents it from stimulating cell proliferation until it is activated by WNT pathway via DSH signal
3 DNA repair mechanisms to know and their normal functions
- Mismatch repair: corrects base pair errors (e.g. G-T). Defective in Hereditary Non-Polyposis Colon Cancer (MUTS alpha = MSH2 + MSH6; MUTS2 beta = MSH2 + MSH3)
- Nucleotide Excision Repair: corrects thymidine dimers from UV light. Defective in Xeroderma Pigmentosum
- Homologous Recombination Repair: BRCA1, BRCA2, and ATM are involved. Deficiencies related mostly to breast cancer, but some others too depending on which protein is mutated.
what neoplasia has n-myc characteristically over-expressed
what neoplasia has c-myc characteristically over-expressed
n-myc: neuroblastoma
c-myc: Burkitt lymphoma
Cell surface glycoproteins used as tumor associated antigens for:
- breast cancer
- ovarian cancer
- colon cancer
Breast cancer: MUC-1
Ovarian Cancer: CA-125
Colon Cancer: CEA
(may be present in many other cancers too)
5 Mechanisms for neoplasia to escape the immune system
- Selective growth: only grow non-antigenic cells due to natural selection
- Loss of/reduced MHC-I, escaping Tc killing but still susceptible to NK cells
- Upregulate Tregs via TGF-beta, which suppresses immune response
- Antigen masking: covers tumor antigens with mucin/glycoproteins
- Express FasL to induce apoptosis of T cells
Pap smear stages
P1: inactive/normal P2: active/normal P3: suspicious, should repeat examination P4: dysplasia P5: neoplasia
CIN stages:
made from resection of cervical epithelium to observe architecture with basement membrane, taken after getting P4/P5 Pap smear
CIN-I: 1/3 of epithelium has dysplasia, low risk (low SIL)
CIN-II: 2/3 of epithelium has dysplasia, high risk (high SIL)
CIN-III: whole epithelium has dysplasia: Carcinoma in situ
If it’s any deeper, it’s invasive carcinoma
[CIN = cervical intraepithelial neoplasia; SIL = squamous intraepithelial lesion]
GIST: what mutation can be used to identify it with immunohistochem?
c-KIT (CD117), a receptor tyrosine kinase. can be mutated in many other cancers too.
Three common translocations seen in B-ALL, and how they impact the prognosis
- t(12;21): more common in children. better prognosis
- t(9;22): more common in adults. worse prognosis
4 WHO categories of AML
- AML with specific genetic mutations to help predict outcome, as in t(15;17), t(8;21), inv(16), and t(11q;invariable)
- AML with dysplasia, which can arise from myelodysplastic syndrome
- AML occuring after genotoxic chemotherapy
- AML-not otherwise specified
5 WHO categories of MDS:
hopefully doesn’t matter but Matolcsy did teach it
- Refractory Anemia: doesn’t respond to anemia treatment
- Refractory Anemia with Ringed Sideroblasts
- Refractory Anemia with excess of Blasts (RAEB)
- Refractory Cytopenia
- 5q minus syndrome: isolated megakaryocyte problem where they are small and proliferative
Ann Arbor Classification:
Staging for Hodgkin Lymphoma
- one lymph node involved
- > 1 lymph node but it’s either above or below diaphragm
- More lymph node regions, and it’s both above and below diaphragm
- Organ involvement: spleen, liver, kidney, etc.
Two good differentiating markers for AML vs ALL
AML: MPO
ALL: TdT
Important mutations for:
Clear cell renal carcinoma
Papillary renal carcinoma
Clear cell: VHL
Papillary: MET