[Question] Difference between denovo_fit and cosmic_fit

[JuseTiZ]

When using cosmic_fit to assign mutational signatures to my samples, I identified SBS1, SBS5, and SBS19.

I then extracted these three signatures to refit using denovo_fit. However, I noticed differences in the distribution of these signatures. For example, SBS19 appeared in samples where it had not been detected previously with cosmic_fit.

Is this discrepancy due to differences in the processing methods of the two functions? If I want to compare the changes in fit after adding some signatures, should I compare the results of two denovo_fit runs (before and after adding the signatures), or should I compare the results of denovo_fit (after adding the signatures) with cosmic_fit?

Looking forward to your reply!