CDH1 and growth hormone-producing pituitary gland neoplasm: However, not all pituitary cells were positive for E‐cadherin, in agreement with previous studies.20 Representative images of E‐cadherin immunoreactivity in normal pituitary and the different IHC semiquantitative scores in somatotropinomas are shown in Figure 1A. Twenty‐eight tumours displayed none or extremely low, negligible membranous staining.