APOA1 and head and neck squamous cell carcinoma: For example, ApoA-I levels are upregulated in the serum of patients with early stage gastric adenocarcinoma, recurrent head and neck squamous cell carcinoma and retinoblastoma and in the urine of patients with transitional cell carcinoma of the bladder, while a nested case-control study reported that HDL-c/ApoA-I levels were positively associated with the risk for the development of breast cancer [79,90,112,113,130,131,139].