Albert: My lab has two sides, 3D printing (technology) development and cancer assays.
On the technology side, the biggest obstacle right now are the machines: the highest-resolution ones for microfluidics (Dilase3D, 5 micron resolution over a 10 cm x 10 cm area) are too expensive (~$200,000) to be widespread, although we have one here at UW, and can only print in one material at a time. We wish they were down to $10,000 and could print in several materials.
On the cancer side, given that we have learned that cancer is a disease that evolves differently in every individual, we need personalized treatments. We need assays that detect cancer early (for prevention) and treatments that stop cancer when it has spread (metastasis). Right now there are very few treatments for metastatic disease, so I think we should try new strategies because the old tenet that metastasis results from an accumulation of random mutations is not credible.