In the pivotal studies comparing LMWH versus VKA in CAT, body weight–adjusted LMWH doses were used.55, 84, 85Data from those studies ruled out a significant LMWH accumulation over time, since anti-factor Xa activity (anti-Xa) remained stable.86Therefore, in spite of the higher risk of recurrence and bleeding in cancer patients, there is no evidence to support routine monitoring of anti-Xa activity to adjust LMWH dose. The gene discussed is TNXA; the disease is cancer.