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Douglas Hanahan , Robert A. Weinberg Hallmarks of Cancer: The Next Generation Cell Volume 144, Issue 5 2011 646 - 674
2000
Douglas Hanahan , Robert A. Weinberg Hallmarks of Cancer: The Next Generation Cell Volume 144, Issue 5 2011 646 - 674
2011
La cellula tumorale acquisisce queste caratteristiche
mediante
• mutazioni
• alterazioni epigenetiche
in un processo mutagenico multi-step
Mutazioni
Mutazioni puntiformi
Brevi inserzioni/delezioni
CNA (copy number abnormalities): gain, loss, amplificazioni
Aberrazioni cromosomiche bilanciate: traslocazioni, inversioni
Mutazioni di oncogeni:gain-of-function, amplificazione, e/o
iperespressione
Mutazioni di oncosoppressori: loss-of-function, delezione, e/o
silenziamento epigenetico
Walther A. et al., Nature Review Cancer 2009
Two forms of genetic instability are described in CRC:•Microsatellite Instability (MIN): characterized by a deficiency of the mismatch repair system that leads to slippage in microsatellites
Chromosomal Instability (CIN): comprise 85% cases and it is characterized by aneuploidy.
Teoria della selezione clonale
Eterogeneità clonale
Più cloni (derivati da una unica cellula di origine del tumore, ma caratterizzati da eterogeneità genetica) possono coesistere contemporaneamente nella massa tumorale
TUMOR
MUCOSA
Colorectal Cancer
Intratumor heterogeneity by double-sampling data
Mean of correlation coefficient in 18 double sampling pairs
Within pairs 0.75
Between pairs 0.19
0.8
Computational Biology Program, Memorial Sloan-Kettering Cancer Center, New York, USA.
The Cancer Genome Atlas (TCGA) project was started in 2006 with the goal of collecting and profiling over 10,000 tumor samples from at least 20 tumor types. Half of these studies have been completed so far. The globally coordinated International Cancer Genome Consortium (ICGC), of which TCGA is a member, will add thousands more samples and additional tumor types
The cancer genome hyperbola
The distribution of SFEs in tumors indicates that the number of copy number alterations in a sample (x axis) is approximately anticorrelated with the number of somatic mutations in a sample (y axis).
We separated cases (84%) with a mutation rate of < 8.24 per 106 and those with mutation rates of >12 per 106 (median number of total mutations 728), which we designated as hypermutated
Mutazioni “driver” che portano a variazioni funzionali importanti per il fenotipo tumorale
Mutazioni “passenger” : neutrali, dovute all’instabilità del genoma delle celluletumorali
Overall, we identified 32 somatic recurrently mutated genes in the hypermutated and nonhypermutated cancers. After removal of non-expressed genes, there were 15 and 17 in the hypermutated and non-hypermutated cancers, respectively
Leucemia Mieloide Cronica (LMC)
Dimostrabile nel 95% dei pazienti affetti da LMC
Il cromosoma Philadelphia: l’anomalia citogenetica responsabile della malattia
1 2 3 4 5
6 7 8 10 119 12
13 14 15 16 17 18
19 20 21 22 x Y
Janet Davison Rowley (born April 5, 1925) the first scientist to identify a chromosomal translocation as the cause of leukemia and other cancers.
Formazione del cromosoma Philadelphia (Ph)La traslocazione t (9;22)
Proteina di fusione con attività
tirosina-chinasica leucemogenica
22
bcr
abl
9
Ph
Bcr-Abl
9+Cromosoma
Cromosoma
Cromosoma
Cromosoma
ABL ABL
Tyr Tyr
BCR BCR
Autophosphorylation by dimerization
P
Phosphorylation of substrates
The constitutive TK activity of BCR-ABL isthe primary factor causing the expansion
of the Ph-positive clone
NUCLEUS
Cell Cycle
BCR/ABL
Paxillin
F-actin
2. Changes in adhesion to stromal layer
General overview
3- Inhibition of
apoptosis
PIK3 -AKT
RAS
JAK-STAT
1. Activation of proliferation
MYC
Glivec (imatinib) Inibitore selettivo della tirosina-chinasi Bcr-AblMeccanismo d’azione
Goldman JM, Milo JV, NEJM 2001, 344:1084-1086
ProteinaBcr-Abl
Substrato
Substrato
Effettore
ATP
P
Y
Y
PP
P
ProteinaBcr-Abl
Substrato
Substrato
Effettore
GLIVEC
Y
Y
Y = TirosinaP = Fosfato
LEUCEMIA PROMIELOCITICA ACUTA
Role of transcription factors involved in promyelocytic acute leukemia
Apoptosis Terminal myeloid differentiation
Oncogenesis
(via p53 and/or Rb)
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