Question

8. Cancer cells often accumulate excessive mutations. In order to give your patient a prognosis, you need to screen for other mutations in the cancer cells. For each mutation, explain whether it would improve the prognosis (make the cancer slower/less of a problem) or worsen the prognosis (make the cancer faster/more of a problem). If a protein is listed by name, then it means we learned about it in class, so you can look up its function in your notes. a. E2F function decreases b. p53 is rendered non-functional c. An actin binding protein that triggers actin filament branching and growth is overexpressed d. Cyclin D is overexpressed

Answer 1

a. If E2F function decreases---- it would improve the prognosis , there will not be cell proliferation (as in normal case, RB restricts cell proliferation by inhibiting the E2F)

b. if p53 is rendered non functional: it would worsen the prognosis, non functional p53 protein cannot regulate cell proliferation and it is unable to trigger apoptosis in cells with mutated or damaged DNA.

c. an actin binding protein that triggers actin filament braching and growth is overexpressed: it would worsen the prognosis, as overexpressed actin binding protein causes metastasis.

d; cyclin D is overexpressed: it would worsen the prognosis, overexpressed cyclin D causes  G1 to S progression of tumor cells.

e. A DNA Repair protein does not fold correctly: it would wosen the prognosis, causes cancer

f.  if retinoblastoma is prematurely phosphorylated : it would worsen the prognosis, function of pRb is to prevent excessive cell growth by inhibiting cell cycle progression until a cell is ready to divide , phosphorylated RB becomes inactive and release E2F trancription factor, which causes cell cycle progression.

g. CDC25 function decreases: it would improve prognosis: Loss of Cdc25 function results in a specific G2 arrest

h. Wee1 function decreases: it would improve prognosis. causes apoptosis of cancerous cells.

i. the estrogen receptor is active in the absence of estrogen: it would wosen the prognosis, it causes breast cancer

j. the anaphase promting complex function decreases, it would worsen the prognosis, causes cancer

k. cytochrome slowly leaks out of the mitochondria: it would improve prognosis, it causes apoptosis

l. Bcl-2 is overexpressed: worsen prognosis, as it is antiapoptotic protein

m. a lamin associated protein cannot bind to DNA properly: worsen prognosis, causes carcinomas