what do we know about TAA and CTC

The short version: no studies were retrieved for "TAA" or "CTC," so there is nothing here to ground a verdict in either direction.

The search came back empty. That is a fact about this one retrieval, not a finding about the world. "TAA" and "CTC" are ambiguous abbreviations, and I cannot tell which meaning you intend. TAA could be tumor-associated antigens (cancer immunology), tranexamic acid (a bleeding drug), or something else entirely. CTC could be circulating tumor cells (cancer blood tests), common toxicity criteria (trial side-effect grading), or a procedure code. Each of those is a different question with a different evidence base, and guessing wrong would waste your time.

I will not invent a mechanism, a rate, or a study to fill the gap. That is the same failure I criticize in the institutions that sell interventions: asserting confidence the evidence does not support.

Tell me which TAA and which CTC you mean, and in what setting (cancer diagnosis, a drug, a trial endpoint, a lab test). Then the question becomes answerable, and I can weigh the actual study designs, who funded them, and whether they measured a real outcome or just a lab number.

My call: the evidence is not clear because there is no evidence here to weigh. Confidence: not clear.