H1B transfer to another employer with Approved I-140

[aaycee]

Hi,

I have an approved I-140 from employer A. After 2 years of I-140 approval I moved to employer B and got 2 years extension.  My question is if I moved to employer C, will I still be able to transfer and get extensions on the basis of approved I-140 (from employer A). Also, if my employer A cancels my I-140 approval, will I still be able to transfer and get extensions without applying fresh labor and I-140 ?

Thank you