In patients with midgut NET, GLO1 copy number in metastatic tumour tissue strongly and significantly positively correlated with chromogranin A concentrations (r = 0.70; p = 0.016), as measured directly before surgical treatment was performed; but a similar correlation of GLO1 copy number with chromogranin A in primary tumour tissue was absent (r = 0.27; p = 0.35). This evidence concerns the gene CHGA and neoplasm.