I downloaded clinical data from cBioPortal in addition to some more files. Among the downloaded files is a seg file of copy number alteration (CNA). Since no transcriptomic data is available, I aim to calculate tumor purity using CNA data, with the PureCN R package. The guide provided at https://bioconductor.org/packages/release/bioc/vignettes/PureCN/inst/doc/PureCN.pdf mentions an interval.file and a vcf.file

Is it possible to calculate the tumour purity using only CNA? if so, how?

EDIT: You can close this question.