immunity to cancer Flashcards
what is cancer a disease caused by ?
an uncontrolled replication of the cell
what do oncogenic mutations in a cell result in ?
in activating the cell cycle and or inhibiting the normal processes that result in cell removal such as apoptosis.
give an example of how infections can cause cancer ?
human papilloma virus (HPV) is an infection driven inflammation.
integration of HPV DNA into the genome of the infected cell leads to the deletion of host genes e.g. E2 E6 and E7.
what does the gene E2 do ?
it is a negative regulator of the HPV oncogenes
what are the E6 and E7 genes for ?
they promote a malignant change in the host cell
how can cigarette smoking cause inflammation ?
it causes an imbalance in the cytokine secretion and inflammatory responses occur.
how does this inflammation lead to lung cancer ?
imbalance in cytokine secretion and inflammatory responses occur. This favours transformation of normal epithelial cells into malignant cells resulting in lung cancer.
what is the intrinsic pathway to cancer ?
This is a series of genetic events e.g. activation of oncogenes, inactivation of tumour suppressor genes which causes neoplastic transformation such as breast cancer.
what is the extrinsic pathway to cancer ?
this is something outside the body that causes cancer
give an example of the extrinsic pathway to cancer ?
Inflammatory leukocytes (white blood cell) and soluble mediators maintain inflammation at a site and this inflammation increases the cancer risk e.g. colon, prostate, pancreas. The cells can form a mass called a tumour
what innate cells are involved in the immune responses ?
macrophages
myeloid derived supressor cells
mast cells
eosinophils
what does the innate cells activation contribute towards ?
the reinforcement of the pro inflammatory milieu ( environment)
how can tumours evade immuno surveillance ?
cancer cells can present different antigens so the body no longer recognises the cancer cell. or cancer cells can release molecules that suppresses the T cell responses. They can recruit the immune cells such as Treg cells that supress the immune response.
what does the cytotoxicity of the bodies own cell depend upon ?
induction of apoptosis and in the innate - NK cells and acquired this is cytotoxic T cells CD8+.
what does the MHC class I expression on the target cell cause ?
inhibition of the NK becoming activated