Question: For how many proteins were targeted therapeutics initially conceived?
About the article "Chemotherapy", section "Cytotoxics and targeted therapies".

Candidate passages:
Targeted therapies are a relatively new class of cancer drugs that can overcome many of the issues seen with the use of cytotoxics.
They are divided into two groups: small molecule and antibodies.
The massive toxicity seen with the use of cytotoxics is due to the lack of cell specificity of the drugs.
They will kill any rapidly dividing cell, tumor or normal.
Targeted therapies are designed to affect cellular proteins or processes that are utilised by the cancer cells.
This allows a high dose to cancer tissues with a relatively low dose to other tissues.
As different proteins are utilised by different cancer types, the targeted therapy drugs are used on a cancer type specific, or even on a patient specific basis.
Although the side effects are often less severe than that seen of cytotoxic chemotherapeutics, life-threatening effects can occur.
Initially, the targeted therapeutics were supposed to be solely selective for one protein.
Now it is clear that there is often a range of protein targets that the drug can bind.
An example target for targeted therapy is the protein produced by the Philadelphia chromosome, a genetic lesion found commonly in chronic myelomonocytic leukemia.
This fusion protein has enzyme activity that can be inhibited by imatinib, a small molecule drug.
Trubion’s product development efforts were focused on three technology pillars: SMIP protein therapeutics, SCORPION protein therapeutics, and TRU-ADhanCe potency enhancing technology for immunopharmaceuticals.SMIP, or small modular immunopharmaceutical, therapeutics are single chain polypeptides comprising one binding domain, one hinge domain and one effector domain designed in an effort to meet predetermined therapeutic specifications for specific diseases.
SMIP therapeutics are mono-specific (they recognize and attach to single antigen targets and initiate biological activity).
Trubion worked on SMIP drug candidates that targeted validated antigens with the same specificity and predictable biological activity as mAbs.SCORPION protein therapeutics are also single chain polypeptides composed of functional domains from naturally occurring proteins.
The difference between SMIP and SCORPION technologies is that SCORPION compounds are multi-specific therapeutics that are capable of targeting two or more antigens simultaneously.TRU-ADhanCe potency enhancing technology was designed to enhance the potency of existing therapies that work through Fc-directed or antibody-directed cellular cytotoxicity, or ADCC.
TRU-ADhanCe technology could be applied late in development to established manufacturing lines and generate candidates with increased ADCC and longer in vivo half lives. 
The movement of so many chloroplast genes to the nucleus means that lots of chloroplast proteins that were supposed to be translated in the chloroplast are now synthesized in the cytoplasm.
This means that these proteins must be directed back to the chloroplast, and imported through at least two chloroplast membranes.
Curiously, around half of the protein products of transferred genes aren't even targeted back to the chloroplast.
Many became exaptations, taking on new functions like participating in cell division, protein routing, and even disease resistance.
A few chloroplast genes found new homes in the mitochondrial genome—most became nonfunctional pseudogenes, though a few tRNA genes still work in the mitochondrion.
Some transferred chloroplast DNA protein products get directed to the secretory pathway (though it should be noted that many secondary plastids are bounded by an outermost membrane derived from the host's cell membrane, and therefore topologically outside of the cell, because to reach the chloroplast from the cytosol, you have to cross the cell membrane, just like if you were headed for the extracellular space.
In those cases, chloroplast-targeted proteins do initially travel along the secretory pathway).
Because the cell acquiring a chloroplast already had mitochondria (and peroxisomes, and a cell membrane for secretion), the new chloroplast host had to develop a unique protein targeting system to avoid having chloroplast proteins being sent to the wrong organelle, and the wrong proteins being sent to the chloroplast.
In most, but not all cases, nuclear-encoded chloroplast proteins are translated with a "cleavable transit peptide" that's added to the N-terminus of the protein precursor.
Sometimes the transit sequence is found on the C-terminus of the protein, or within the functional part of the protein. 
Clinical Therapeutics 
The movement of so many chloroplast genes to the nucleus means that lots of chloroplast proteins that were supposed to be translated in the chloroplast are now synthesized in the cytoplasm.
This means that these proteins must be directed back to the chloroplast, and imported through at least two chloroplast membranes.
Curiously, around half of the protein products of transferred genes aren't even targeted back to the chloroplast.
Many became exaptations, taking on new functions like participating in cell division, protein routing, and even disease resistance.
A few chloroplast genes found new homes in the mitochondrial genome—most became nonfunctional pseudogenes, though a few tRNA genes still work in the mitochondrion.
Some transferred chloroplast DNA protein products get directed to the secretory pathway (though it should be noted that many secondary plastids are bounded by an outermost membrane derived from the host's cell membrane, and therefore topologically outside of the cell, because to reach the chloroplast from the cytosol, you have to cross the cell membrane, just like if you were headed for the extracellular space.
In those cases, chloroplast-targeted proteins do initially travel along the secretory pathway).
Because the cell acquiring a chloroplast already had mitochondria (and peroxisomes, and a cell membrane for secretion), the new chloroplast host had to develop a unique protein targeting system to avoid having chloroplast proteins being sent to the wrong organelle, and the wrong proteins being sent to the chloroplast.