Impact of denial of PERM/I-140 with new employer if one already having I-140 from previous employer.

I have approved I-140 with Employer A. I joined employer B sometime back who is starting my PERM processing to continue my green card process.If it gets denied at PERM stage or I-140 stage, will I lose my green card eligibility in long run and ability to get extensions in short term?Thanks in advance.