Summary YR 2 CONTENT

Cancer cell biology
Tumour heterogeneity:
Tumours demonstrate distinct morphology and phenotypic
profiles
Occurs between tumours and within tumours




DNA mutations: change in the sequence of bases, can occur randomly, replicative
damage,mutagens
Key mutations:
 Substitution- single nucleotide is replaced- can be silent due to the degenerate
nature of the genetic code
 Deletion- single nucleotide is removed
 Insertion- single nucleotide is added

Main pathways implicated in genomic instability:
 Base and nucleotide excision repair
 Mismatch repair
 Double strand break repair
 DNA replication
 Chromosome segregation
 Telomere maintenance

Characteristic features of cancer genomes:
 Whole genome duplication
 Chromosomal loss and gain
 Translocations
 Hypermutation

Cancer can arise from the expression of mutant forms of protein:
 Extra and intra cellular signalling molecules
 Signal receptors
 Signal transducing proteins
 Transcriptional factors
 Cell cycle control proteins
 DNA repair proteins
 Apoptotic proteins eg tumour suppressors that promote apoptosis and
oncogenes that promote cell survival