B‐Lymphocyte Stimulator in neuroendocrine tumors: correlation with disease behaviour

Aim of the study To test B‐Lymphocyte Stimulator (BLyS) as a new serological marker in the follow‐up of patients with neuroendocrine tumors (NET). Methods Eighty‐one consecutive NET patients and 56 controls were enrolled in the study. Patients were classified in 2 subgroups: persistent but stable disease or remission (n = 45) vs patients with recurrent disease (progressive patients, n = 36). BLyS and Chromogranin A (CgA) serum levels were analyzed by ELISA. Results BLyS levels were more elevated in NET patients than in controls (1153±529 pg/ml vs 655±158 pg/ml; p <0.0001) and correlated with tumor differentiation (1058±398 pg/ml in gastroenteric G1‐typical lungs vs 1325±640 pg/ml in gastroenteric G2–atypical lungs; p=0.026). Stable/remission patients displayed lower BLyS than progressive patients (889±251 pg/ml versus 1461±623 pg/ml; p <0.0001). BLyS did not change in patients who remained stable after 6.6±2.8 months (from 864± 283 pg/ml to 809±235 pg/ml), while further increased in patients with disease progression (from 1575±810 pg/ml to 1887±1163 pg/ml; p=0.045). Whereas, CgA showed contradictory changes. Metastatic patients displayed higher BLyS than non metastatic (1391±724 pg/ml vs 1079±422 pg/ml; p=0.022). Conclusion Elevated BLyS serum levels characterize more aggressive NET patients. BLyS appears as a new potential prognostic marker in the follow‐up.