Cancer Biology (lectures 1 & 2) 20202021 PDF

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Lecture notes on lectures 1 to 2 of the academic year 2020-2021 for Cancer Biology course....

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Cancer Biology (lectures 1 & 2) 2020-2021 Stem Cells in Cancer • • •

Genetic predisposition and environment Accumulation of mutations Stage at diagnosis is key to survival

Epidermal Proliferal Units • • •

Stem cell in the middle of each skin unit Unipotent Asymmetric and symmetric division control tumour growth

Tumours •

•

• • •

From murine transplantation (mice) o Showed stem cells exist in tumours still o Cancer initiating cells are homologous to stem cells Human skin cells have different growth patterns o Tight = cancer o Loose = stem cells o Other = skin cells Holoclone – the original cancer cell Paraclone – stem cell in a tumour In lab you can stain and visually see different cells within the cancer

Therapeutic Resistance • • •

Stem cells are 10 times more resistant than cancer cells and often survive radiation Usually only kill some, so some are left for recurrence Stem cells cause tumour recurrence

Metastasis • •

• • •

Skin is very tightly packed, so tumours will be too Changes in epithelial to mesenchymal cell (EMT) o Lose keratin, cadherin and cell adhesion o Necessary in wound healing o Cancer hijacks this to spread So, by this change they can spread Motile amoeboid CD44 cells spread Can go back and forward genetically and induce o Only found in melanomas

Clinical • •

Pathologists don’t see EMT cells in tissue specimens but do in the lab Could not be visible?

Amoeboid Cells • •

Living cells should stick at bottom of plate and dead should float But living amoeboid cells float o Can revert to epithelial cells (reverse EMT) o Keratin isn’t formed by amoeba or floating dead cells o Cancer marker o In fact, no usual cancer markers show up in them o But express other markers

Markers • • •

Used to see if cancer is bad or fine Amoeboid specific genes affect this They identify previously invisible genes and cells to cancers

EMT Cells • • •

Epithelial Mesenchymal Transition EMT is more resistant than even stem cells o Also give recurrence Some drugs kill EMT cells o This kills cancer at root and shouldn’t recur...