Genetics Flashcards
Lung cancer
List x2 mutations and x1 rearrangements:
Mutations:
EGFR (young asian, light/non smoker)
K RAS
Rearrangements:
ALK (younger than EGFR, light/non smoker, highter rate of met)
+++++++
Molecular genetics: (10-20 mutations) -> important for pathologists as guides treatment
Epidermal Growth Factor Receptor: good prognostic indicator (~10% adeno), more common in non-smokers,
asians, females
ALK: (~5% adeno)
KRAS: poor prognostic indicator
TP53, Rb: both SCC and small cell
Medulloblastoma subtypes and features
Overall the vast majority (94%) of medulloblastomas arise in the cerebellum and the majority of these, from the vermis (75%). They tend to protrude into the fourth ventricle from its roof, and may even grow directly into the brainstem. This pattern is particularly common in group 3 and group 4 and in some SHH-activated tumours.
Other areas are less common and are seen more frequently in older children and adults. In such cases, the tumour is also more likely to be poorly marginated and demonstrate larger cyst formation. Adult medulloblastomas are usually located laterally, in the cerebellar hemispheres, with only 28% centred in the vermis; these are most commonly of the SHH-activated tumorus.
The cerebellar peduncle epicentre is almost exclusively seen in WNT-activated tumours.
==cerebellar peduncle/foramen of Luschka==
very likely WNT-activated tumours and therefore best prognosis
==cerebellar hemisphere==
very likely SHH subgroup and therefore intermediate prognosis
likely desmoplastic/nodular/medulloblastoma with extensive nodularity (MBEN)
==midline==
may be group 3, group 4 or SHH
typically infants with a tumour with ill-defined margins but prominent enhancement: likely group 3 (or SHH) and therefore worst prognosis
typically children with a tumour with well-defined margins but mild or no enhancement: likely group 4 and therefore slightly better prognosis
adults with variably defined and variably enhancing tumours: most likely SHH; haemorrhage raises the probability of group
