Expression-pattern of estrogen- and progesteron-receptor in gastroenteropancreatic neuroendocrine tumours

Expression-pattern of estrogen- and progesteron-receptor in gastroenteropancreatic neuroendocrine tumours

Gastroenteropancreatic tumours may present as metastatic disease without known primary site. Although the morphologic pattern and hormone-production may be indicative for the primary site, surgical exploration may be necessary and successful. Recently, data has accumulated on the expression of estrogen-receptor in pancreatic neuroendocrine tumours. Moreover, we observed estrogen- and progesteron-receptor expression on non-neoplastic islet-cells. This prompted us to analyse this finding in GEP neuroendocrine tumours.

Here, we report on the expression pattern of estrogen- and progesterone-receptor in gastroenteropancreatic neuroendocrine tumours. We analysed estrogen- and progesterone-receptor in 69 foregut GEP, 25 midgut GEP and 7 hindgut GEP. Namely, the foregut GEP included 53 pancreatic NET. All tumour samples were evaluated by to pathologist and a consensus immunoreactivity score according to Remmele (0 – 12) was assigned. An immunoreactivity score ≥2 was regarded as positive.

Overall, according to this definition 17 cases (17%) were estrogen-receptor positive and 46 (46%) were progesteron-receptor positive. When we compared pancreatic NET to all other GEP-NET as well as to foregut, midgut and hindgut NET, the expression of estrogen-receptor did not differ significantly between the groups. However, expression of progesteron-receptor was more often expressed in pancreatic NET than in the other GE-NET (81% vs. 8%, p< 0.0001). This difference remained statistically significant, when pancreatic NET were compared to foregut NET (81% vs. 13%, p< 0.0001), to non-pancreatic midgut NET (81% vs. 8%, p< 0.0001) and to hindgut NET (81% vs. 14%, p= 0.0039).

Biospies of 83 metastases were evaluable in 45 cases. Estrogen-receptor expression was rare (IRS ≥2 in 3 nodal metastases of pNET and 4 nodal metastases of non-pNET). However, progesteron-receptor expression was found in only one nodal metastases of non-pancreatic origin, whereas 15 metastases of pNET were positive for PR.

These data clearly indicate, that progesteron-receptor expression may be of value for identifying the primary in cases of NET-metastasis of unknown primary.