Figure 4. Aggregate analyses of acetylated polyamine derivatives in cancer patients with different levels of Covid-19 severity. For each patient, the sum of the normalized peak areas corresponding to N1-acetylputrescin, N1-acetylspermidine, N1,N12-diacetylspermine and N1,N8-diacetylspermidine were calculated and shown with black bars indicating p-values.