In my opinion, the decimal numbers in the table represent the expression of the proteins, according to what is written in the caption of the supplementary material: "Additional file 2: Expression and interaction data related to normal and cancer conditions of five tissues"
Even if the numbers are quite strange because they are recursive somehow.
If the data file has no column headers and the file structure is not explained in the paper, then you should contact the authors.
Authors no answer. In paper no things about data structure.