PPIB and squamous cell carcinoma: We observed that high intakes of β-carotene, α-carotene, β-cryptoxanthin, lycopene, and vitamin C were associated with a reduced risk of squamous cell carcinoma, while high intakes of β-carotene and α-carotene lowered the risk of adenocarcinoma, and both medium and high intakes of β-cryptoxanthin and lycopene reduced the risk of small cell carcinoma.