Except for the transformation problem, which completely invalidates Marx's theory.
The labour theory of value is a misnomer. It isn't a theory at all, its just a definition. It can't be invalidated. Marx never called it a theory himself. The transformation problem merely shows that the 'labour theory of value' is not as useful as Marx would have hoped - it fails to demonstrate nicely the theory (and this is a theory) of the tendency of the profit rate to fall. This problem doesn't mean that the profit rate doesn't tend to fall. [The transformation problem is the problem of showing that the total surplus value is the same as the total profit].
While I'm on it, Hegel never had any doctrine about the interpentration of the opposites. That's Engels' expression. Engels also talked about the identity of opposites which is much closer to what Hegel was on about. Engels was trying to find dialetics in nature (ie. very general laws of nature) which is why he gives dialectics a dynamic spin. I think he was misguided on this. However, he's still well worth reading on Hegel & dialectics etc.


