Lewis antigens and argyrophilic nucleolar organizer regions staining for assessment of potential malignancy of adenomatous polyps of the gastrointestinal tract in children

Adenomatous polyps (AP) of the gastrointestinal tract in children are very rare. Because of their potential malignancy, they are of great clinical imp ortance. There is little experience in the management of children with AP. The immunohistochemical expression of the Lewis blood group antigens (BGA) (sialosyl-Le(a), Le(a), Le(b), Le(x), and Le(y)) and the number of activate d nucleoli with the silver staining method for nucleolar organizer regions (AgNORs) were studied in two children with AP, In a girl with isolated AP o f the stomach and colon, it was found that antigens Le(b) and s-Le(a) were expressed extensively in the gastric adenoma, and sialosyl-Le(a) throughout the entire length of the rectal adenoma crypts, but in the AgNORs stain th e number of nucleoli ranged from two to four, evidencing changes of a benig n character. In the case of familial adenomatous polyposis diagnosed in a 9 -year-old boy, in some colonic adenomas the number of activated nucleoli wa s greater than five, and the Le(b) antigen was expressed in superficial epi thelial cells in one of the adenomas, Also, extensive expression of antigen s Le(y) and s-Le(a) throughout the entire length of the crypt in another po lyp removed was observed, We believe that immunohistochemical study of the intensity and extent of the expression of Lewis BCA in the polyp tissue sim ultaneously with the determination of the number of activated nucleoli by t he AgNORs staining method can be helpful in better analysis of cytological risk factors of a malignant transformation.