Flashcards in Aetiology of Cancer and Neoplasms I Deck (71):
What is one defining feature of Cancer?
Rapid creation of abnormal cells that grow beyond usual boundaries
What is the spreading of Cancer reffered to as?
What are Malignant Neoplasms?
Carcinoma in Situ and cancer
What is the difference with a Benign Tumour in terms of spreading?
Dont metastasize, remain encapsulated by connective tissue fibrous sheath
What are the 5 main groups of Cancer?
Carcinoma - skin
Lymphoma - Lymph
Leukaemia - blood
Sarcomas- connective tissue
CNS tumours - brain and spinal cord
How do Benign tumours appear microscopically?
Innocent, tumour staying localised and remains encapsulated
What are Malignant tumours?
Referred to as cancer, can invade and destroy structures, migrate to sites as they metastasize
What type of Benign tumour would Glands have suffix of?
What type of Benign tumour would Surfaces have suffix of?
What type of Benign tumour would Mucous surfaces have suffix of?
What type of Benign tumour would Hollow masses have suffix of?
Where are Sarcoma cells in malignant tumours derived from?
Where are Carcinoma cells in malignant tumours derived from?
What 2 Tumours are definitely malignant?
Melanoma and Lymphoma
Why are Cancers bad for us?
Local tissue destruction
How are Cancers classified?
Based on grade - how close cells resemble tissue of origin
Stage - how far spread from nidus
What is TNM in the common staging system?
Why is Staging import?
For treatment and to factor 5 year survival rate
What test is used to Specify Tumours?
What is a Neoplasm?
A mass formed by autonomous proliferation of cells or new growth
What does Abnormal proliferation of cells result in?
Neoplasm or tumour
Are neoplasms malignant?
Not all e.g uterine fibroids
What is Cell division dependant on?
Signals and Sensors
What happens of signals or sensors become damaged?
Cell division is unregulated can result in tumour
What are the 3 Main types of Body cells during cell division?
Cells that never divide
Cells that retain ability to divide but dont
Cells that routinely divide and can alter rate of division
How do Cells duplicate in a Eukaryotic cell?
What are the 4 Phases of Cell cycle?
What happens in G1?
High rate metabolism, proteins synthesis, organelles duplicate and centriole replicates
What happens in S phase?
DNA replicated, synthesis of new histones and assembly of new chromatin
What happens in G2 phase?
Synthesis of enzymes and proteins, replicate of centrioles done, transport
What happens in M phase?
Mitosis and splitting of genome
What are 2 critical points for dividing cell
G1/S boundary - dna synthesis
G2/m boundary - mitosis
What happens to cells that fail to undergo mitosis?
What are the important factors that regulate entry of cell in S phase?
What allows proper functioning of Cdk 2?
What allows proper functioning of Cdk4,6?
What do growth factors activate and produce?
What does Cyclin D activate?
What does Cdk 4 do?
Phosphorylates pRband prevents inactivation of E25-1
What does E2F-1 do?
Binds with enhancer sequences activating transcription for dna synthesis
What happens to these regulations once the S phase begins?
pRB is dephosphorylated to prevent further rounds of DNA replication Cyclin D destroyed
In the G2/M phase what protein kinase is present?
Cdk 1 With Cyclin B
What does Cyclin B do?
Cell switch - modifies proteins
Sets in motion a sequence of changes
Activated only at G2/M boundary for mitosis
Post mitosis what happens to inactive heterodimer?
Phosphorylated at threonine 14, tyrosine 15
At the G2/M phase what removes phosphates?
What is Wee1?
Phosphorylation to ensure complete inactivation adding 2 phosphates to Cdk1 and thrty14,15
What does WEE1 prevent binding of?
ATP to Cdk1 - first step of phosphorylation of other proteins
What transcription factor activates gene coding?
In non-dividing cells why is E2F-1 inhibited?
Bound to protein pRb
What are 3 signals that lead to arrest of cell growth?
Mitogen withdrawal, Loss of adhesion, Contact inhibition
What 2 CKI's are inhibited to prevent DNA synthesis?
P16 ink4a P27kip1
What is P53?
Tumour surpressor gene found on chr 17 involved with dna repair
What does Increased conc of P53 activate?
What inhibits G1 CDK's?
p21 cipi1 to prevent replication of defective DNA
What is Apoptosis?
Programmed cell death
What is Apoptosis characterised by?
Cell shrinkage, Cell contents in blebs, Chopping up DNA, Secretion of cytokines
What is the Extrinsic pathway?
Instructed death - viral infection
What is the Intrinsic pathway?
Default death - absence of growth factors
What is stress activated apoptosis?
Direct activation of mitochondria and protein kinase P38
What is Senescence?
Irreversible cell cycle arrest
Whatr is replicative senscence?
What is stress induced senscence?
DNA damage p16
What is oncogene induced senescene?
Oncogene activation p53
What is replication stress induced senescence?
Haemophiatic stem cells
What is developmental senescence?
What is cell-cell fusion?
What are telomeres?
Chr capping function, prevents ends of chr from seen as double stranded breaks
What is telomere shortening?
DNA polymerase cant lengthen terminal section
What is angiogenesis?
Own blood vessels for blood supply to cancer growth
What growth factors switch angiogenic factors on?
VEGFR , bFGF