Oh yeah - "These findings indicate that the biological responses to cannabinoids critically depend on drug concentration and cellular context." Is the bottom line in the cited study.
They pre-treated the cancer cells in the study with several chemicals, then exposed them to several
synthetic cannabinoids and endocannabinoids (made by your body). At lower treatment levels, delta - 9 tetrahydrocannabinol induced the cancer cells to kill themselves (previous studies have shown this to be the case with some lung cancers) and at higher doses it caused them to proliferate. The vehicle used was smoked cannabis.
A side note I bring up often: inhaling the smoke from burning vegetable material is not good for your health. Smoke contains stuff like carbon monoxide, acetone, styrene, anthracine and carbon particles (soot). It is not good for you, the solvents, plastics and toxins (like the CO) are what gives you the "couch-lock stone", cannabis vapor and 'medibles' do not contain that stuff. If you are going to consume cannabis, keep this in mind and go for a safer alternative than inhaling the smoke from burning material.