Neoplasia Flashcards
Causes of genetic changes in neoplastic cells
Single inherited
Multiple inherited
Acquired somatic mutations
Single inherited gene examples
Neurofibromatosis (elephant man)
Nonfx-al neurofibromin pro - allow many cancers to form (usually benign then go mailgnant)
BRCA1&2
Repair double stranded DNA damage by resetting ends away and using a template. 1 mutated copy - much higher breast/ovarian cancer risk
What is neurofibromin
Tumour suppressor pro
The ras inhibitor, stops ras from being constitutively active
Intrinsic causes of acquired somatic mutation
Reactive O2 species (produced in krebs cycle)
Dna pol errors
Extrinsic causes of acquired somatic mutation
Chemicals Radiation Viruses UV light Smoking
Genetic and Acquired somatic mutation (multifactorial) example
Hereford cattle pigmentation around eye. No brown colour - more succeptible to ocular neoplasms
This pigmentation is highly heritable, but sun exposure also contributes to tumour incidence.
Where genetic changes can occur that result in neoplasm
GFs and GF receptors (always active mutants)
Signal transduction pros (activate cellular growth)
TFs (directly incr gene expression)
Anti-oncogenes (tumour suppressors turned off)
DNA repair genes (can’t fix mutations)
p53 fx
TF that can promote transcription of many diff genes, so act result in apoptosis, senescence or quiescence
eg apoptosis: p53 upregulates BAX and BAK
Benign neoplasms
Well differentiated Uniform size and shape Nucleus has normal morphology Few mitoses Encapsulated and expansive No metastases
Malignant neoplasms
Anaplastic Pleomorphic Abnormal nucleus morphology Incr (sometime bizarre) mitosis Non encapsulated - infiltrative Metastises
Direct neoplasia effects on animal
Compress tissue Compress/block blood vessels Block tubular organs Organ rupture Haemorrhage
InDirect neoplasia effects on animal
Remote effects caused by tumour cell products aka paraneoplastic syndromes eg cachexia
