靶标药, 打靶不打杆, 治标不治本

How close to cure is personalized 个人化, or targeted therapy 靶标疗法???

Not even close. Long long way to go.

Anyone who has a little bit biochemistry knowledge can explain this central dogma

DNA -> mRNA -> Protein

Now, as I have put it before, all cancers are rooted in the DNA, whether it originated from a single point mutation, or chromosome translocation/ gene fusion, or oncogenic acquisition.  So, unless you kill all malignant and pre-malignant cells with such cancer roots, or reverse the DNA/chromosomal damage/alteration back to original genome perfection, you will always have cancer or at least dormant ones.

Targeted therapies, so fas as I am aware, hit the Protein, and most likely the protein being an enzyme.  For example, Gleevac binds to the fusion tyrosine kinase and kills its activity, almost cures CML. Almost. 

But not yet.  Cancer is in the DNA (root cause: bcr-abl gene fusion), this drug only kills the protein. So what happens?  As long as life goes on, cell divides and DNA mutates.  DNA in cancer cells mutates more frequently, and DNA in cancer patients who receives chemo and radiation (diagnostic & therapeutic) mutates even more quickly, thus it is only a matter of time that mutant version of the enzyme will arise and the drug loses its effectiveness. 

If the drug holds down the cancer from causing damage or death long enough and the patient dies of other causes than the cancer, we'd say the drug has been as good as a cure.  "As good as", but not "is".