


ASCO 2017 – Let’s talk about NETs #ASCO17

It’s been 10 years since I saw a scalpel (….but my surgeon is still on speed dial)

Neuroendocrine Cancer: Nodes, Nodules, Lesions (and false alarms!)

The expression of antigen Ki67 is strongly associated with tumour cell proliferation and growth, and is widely used in routine pathological investigation as a proliferation marker. The nuclear protein Ki67 (pKi67) is an established prognostic and predictive indicator for the assessment of biopsies from patients with cancer. It’s therefore an excellent marker to determine the growth fraction of a given cell population. The fraction of Ki-67-positive tumour cells (the Ki-67 labelling index) is often correlated with the clinical course of cancer. Pathologists normally need to count about a thousand cells in order to determine the percentage of cells that are Ki67 positive – thus why you see Ki67 expressed as a percentage. 0% is the lowest, 100% is the highest. Often, they add greater or less than signs depending on the sample involved, i.e. >5% or <5%. There are other measurement systems in place, mainly Mitotic Count which tends to be more frequently used for Lung NENs. The Ki-67 index can usually be determined, even in cases of small biopsies but Mitotic rate counting requires a moderate amount of tumour tissue (at least 50 HPFs or 10 mm) and may not be feasible for small biopsies.