Limitations of Culling PATS/KOH/PAS method of differential diagnosis of metastatic colorectal cancer.

Investigations of Culling et al. showed the possibility of using KOH/PAS effect (visualisation of C7 and C8O-acylated sialic acids characteristic to colon mucin) for differential diagnosis of metastatic colorectal cancer. Our investigations revealed, however, KOH/PAS positive mucin prevailing in some cases of gallbladder, pancreatic and gastric cancer. This makes serious limitation of Culling method in the routine diagnostic work.