p53 vs RAS (most common mutation in cancer is?)

[moodle]

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Hey all,

Quick question: I can't remember where I saw this, but I'm sure I ran into this question in the past (just can't remember where exactly).

In general terms, what is the most common mutation seen in cancers? p53 or Ras?

The answer choices had both p53 and RAS vs a bunch of garbage that you could easily eliminate. My friends and I never were able to answer this question...

I'm inclined to go go with RAS. In Pathoma, Dr. Sattar states in the neoplasia lectures (carcinogenesis part II 13:00-13:30 at 1X speed) that "up to 70 to 80% of human tumors actually have a RAS mutation associated with that tumor"

I also think that p53 has a huge role to play too (I mean we've heard that p53 is the most important protector of the genome/"guardian of the genome" etc since freshman year of college).

So which is it?! p53 or RAS as the most common mutation? Thanks everyone!

 

[J ROD]

honest answer is we probably do not know. Only think we do. Just know they both are important.

Like drinking milk is bad for you one week and good for the next. Now, smoking will mess you up!

 

[Phloston]

That question doesn't actually make sense. That's like asking "what is the most typical student at a university?"

So anyone who gives you a concrete answer to that is lying to you.

In general, RAS mutations result in a constitutively active G-protein. p53 mutations result in failure of cell cycle arrest.

But if it had to be one or the other, I'd go with p53. If you think about colon cancer for instance, the mutation sequence is generally APC --> KRAS / DCC --> p53. And it's not invasive until p53 has mutated. Although RAS can be non-specific, I generally hear it associated with colon cancer, whereas we know p53 mutations (Li-Fraumeni) are more ubiquitous cancer-wise.

 

[Double A]

p53

 

[Nephronlearner]

I would also go with p53 since that mutation seems to be present in nearly all types of cancer. RAS, while common, probably isn't THE most common one. Since it is a cell cycle regulator that prevents cell division - it makes sense that it has to get mutated for cancer to develop. (otherwise regardless of whatever other mutation you get - p53 would just block the cell cycle)... that would be my guess. Someone correct me if I am wrong!

 

[BA11]

P53 is the best answer, its estimated that its involved in over half of all cancer cases.

Of course, such things are very fluid when it comes to research. Cancer genetics is a rapidly evolving field.

 

[moodle]

Thanks guys, I guess p53 makes a bit more sense than RAS.

 

[k-bourne]

p53 is the most common mutation found in more than half of human cancers, although usually associated with other mutations.
RAS mutation is like second place found in 15-20% of cancers, but is more common than p53 mutation in some cancers like
pancreatic and endometrial CA.