Things I detected when exploring cancer ferritin.
The researchers also found that women with breast cancer had much higher levels of ferritin, an iron transport protein, in their breast fluid, which was 5. X higher in women with breast cancer. 
Overall, there were no associations between the risk of colorectal cancer and any of these indices except for serum ferritin, which showed a significant inverse association. 
With cancer ferritin concentration in the blood increased because of its active secretion, and due to the increased cellular debris due to chemotherapy.