The cancer thing gets thrown around too much. The real truth is that most people are not special human beings who show their best in the face of disaster. Most people kind of go with the flow.
Put Marbury on some dysfuntional poorly run franchise and you get a dysfunctional problematic player. But much like Randy Moss in the best situation you might get someone surprisingly good..
But the Nets/Suns both traded him and immediately became NBA title contenders for several years. Part of that is the talent they brought in to replace him, but by all reports he was a toxic teammate in both organizations. Neither was particularly dysfunctional while he was there or after he was gone.
A quote from the NYTimes from a Nets teammate:
In 1999, with the Nets, one Nets player said this about Marbury:
“He gets on Kerry Kittles and Keith. He doesn’t respect them as players, and I think that hurts us. I hate to see expressions on guys’ faces now. When they walk into the locker room, their heads are down and nobody talks to anybody.
“He’s a great player. You can’t take nothing away from him. But we see right through him. Maybe it’s not even his fault. They put him in the driver’s seat, handed over the keys and said, ‘Make us go.’ At 22 years old, that’s a lot to ask.”