Table 2.

Comparison among patient-derived colorectal cancer model systems.

Features	Cell Lines	PDX	PDTO
Initiation success rate	Low	Moderate	High
Possibility of expansion	Very high	Moderate	High
Time consuming	Low	High	Moderate
Cost	Low	Very high	High
Expertise	Low	High	High
Ease of maintenance	High	Moderate	Moderate
Amenability for genetic manipulation	High	Low	High
Ease of downstream assays	High	Low	High
High-throughput drug screening	Very high	Low	High
Low-throughput drug screening	Very high	Moderate	Very high
Modelling early stage CRC	No	No	Yes
Autologous normal controls	No	No	Yes
Isogenic control by genome editing	Yes	No	Yes
Patient-specific	No	Yes	Yes
Save animal testing	Yes	No	Yes
Recapitulation of tissue features	Low	High	High
Need of specialized facilities	Low	High	Moderate
Cell-matrix interaction	No	Yes	Yes
Lack of microenvironment	Yes	No *	Yes

* Non-human microenvironment.