E=mc2 is most known formula. This formula is the only ground in quest for holy fusion. The formula also called mass-energy equivalence.
It is quite easy to demonstrate that the formula is not correct.
If we open Einstein's article “Does the Inertia of a Body Depend on its Energy-Content?” and carefully read how the famous equation was derived, we will see the following:
1. Body emit the light
2. Complicated reasoning with switching reference frame back and forth
3. Final conclusion that energy of the light was withdrawn from kinetic energy
There is always a reference frame where body is stationary with zero kinetic energy. Where the energy of the light came from?
The formula is not correct. It is not possible that in the moving reference frame the energy of the light came from kinetic energy while in the stationary system it came from something else.