Table 1. Expression of members of the RET pathway in breast cancer cell lines: qualitative analysis of RET, its ligands and co-receptors in MCF7 and T47D.

Genes	MCF7	T47D
RET	+++	+
GDNF	+/−	-
NRTN	++	++
ARTN	++	+++
PSPN	++	+++
GFRA1	+	-
GFRA2	-	+
GFRA3	+/−	+/−