without normal control, can I know a gene's expression level only by its expression in the tumor

Question

[weaponhu]

I am analyzing LUAD(lung adenocarcinoma) gene expression data these days. The number of total samples is about 580, but only 58 of them has normal-tumor paired expression, from which I can calculate the expression level. The question is how can I evaluate the expression level of the rest samples, which only have tumor expression? Many thanks

[Sirus]

Are they from the same tumor or they are different ones ?

[parvathi.sudha]

Hi, From where did you get LUAD normal sample data for gene expression(DNA)? I couldn't find it in the TCGA.