Table 12.

In vitro models: 3D cell cultures.

Type	Source Cell/Tissue	Key Features
pNET spheroids	pNET cell lines: BON-1 and QGP-1 Human lung neuroendocrine cell line: H727	Three-dimensional spheroids start forming by day 3 of cell plating and contain highly proliferative cells at the periphery and a necrotic center, proposed to be useful models for in vitro drug screening [344].
SBNET spheroids	Patient SBNETs	Cultured with the help of extracellular matrix (Matrigel); doubling time was 14 days; expressed synaptophysin, chromogranin and SSTR2; undergo apoptosis with rapamycin treatment [345].
pNET spheroids	Patient pNETs	Primary tumor cells isolated from pNETs and cultured in vitro to form islet-like tumoroids that retain a neuroendocrine phenotype and are viable for at least 2 weeks in culture for drug testing [346].