I'm a big fan of fundersclub.com. With a single investment (min 10K) you can hit 10 or so of the best companies from the winter or summer batch of YCombinator.
You need an invite to join, and you must be an accredited investor. If you need an invite contact me and I'll refer you.
By the way, this is very risky and very illiquid. I don't recommend investing more than 5% or 10% of your net worth. And don't expect to be able to cash out on anything for 5 to 7 years.
I have recently lost a good friend in her 40s to multiple myeloma. It isn't named in this article, but would this treatment work for that cancer as well? Both seem to target B cells.
CAR therapy requires identifying a broadly expressed target; it looks like there are a few candidate antigens being evaluated for MM but I don't know if any of the studies have published significant results yet.