BLOOD-GROUP ANTIGEN EXPRESSION IN PAPILLA RY CARCINOMA OF THE THYROID- AN IMMUNOHISTOCHEMICAL AND CLINICAL-STUDY ON THE OCCURRENCE OF LEWIS-ANTIGEN, ABO-ANTIGEN, AND DERIVED-ANTIGEN

Nine monoclonal antibodies, lectin from Ulex europaeus and neuraminida se enzyme were employed to demonstrate the occurrence of type 1 and ty pe 2 blood group antigens in 104 cases of papillary carcinoma of the t hyroid. The reagents applied, recognize the following blood group rela ted antigens: CA-50 (sialylated type 1 precursor), CA-19-9 (sialylated Le(a)), Le(a), Le(b), A, B, H, Le(x), sialylated Le(x), and Le(y). Im munohistochemical studies revealed that papillary carcinoma of the thy roid, in contrast to histologically normal thyroid tissue, is characte rised by a progressive expression of blood group antigens. Most tumour s (84%) reacted with C-50 antibody, whereas only a minority of the tis sues demonstrated the CA-19-9 antigen (38%). Type 2 structures Le(x) ( 47%) and Le(y) (13%) were found less often than their corresponding ty pe 1 isomers Le(a) (71%) and Le(b) (62%). Desialylation with neuramini dase increased the Le(a) and Le(x) staining intensity in 27 and 44 cas es, respectively. Of the A, B, H antigens the A determinants encounter ed most frequently (24%). Comparative examinations of sequential secti ons of the same tumour revealed coexpression of type 1 antigens in the same areas. In carcinomas showing type 1 and type 2 antigen reactivit y, a complementary distribution of the structures in different tumour areas was often demonstrated. Some tumours presented combined type 1 a nd type 2 antigen expression in the same cells, however, in distinct a reas within the cell. A follow-up examination was carried out in 68 of the 104 cases. The observation time ranged from 12 to 217 months. Thi rteen patients suffered from recurrence, of which 7 died. While lympha tic metastases occurred in 39 tumours, distant metastases were detecte d in 6 patients. Most of the recurrences were found in patients with t umour classification pT4 (n=19), whereas none of the pT1 carcinomas (n =20) showed recurrence. The clinical results were compared to the bloo d group antigen expression results. There was no correlation between a ntigen expression and differentiation degree of the tumour. The pT4 tu mours showed a significant higher expression of the CA-50, CA-19-9, Le (a) and Sialyl Le(x) structures. Carcinomas expressing the Le(y) antig en were associated with a significant higher level of metastasizing ca pacity. The Le(y), H type 1 and H type 2 antigens occurred more freque ntly in recurrent tumours (n = 14). In contrast, none of the patients whose carcinomas expressed the A-antigens (n=14) suffered from a recur rence or hematogenous metastasis. Multiple stepwise regression analysi s was carried out to check the importance of each staining and clinica l factor. Ln this analysis, 'distant metastasis' was the most importan t parameter, whereas the staining results were of minor statistical im portance.