Extended Data Fig. 6: Loss of RB promotes alternative pathways toward gaining metastatic competency.

(a) H&E photomicrographs of metastases that formed from KPRb^TR/TR tumours.

(b) Immunofluorescence analysis of KP and KPRb^TR/TR tumours for co-expression of HMGA2 and NKX2–1.

(c) IHC staining of serial sections from KP and KPRb^TR/TR tumours for HMGA2 and FOXA2. Orange dotted lines outline mutually exclusive staining and red dotted lines outline co-expressing staining patterns. Quantification of staining pattern (right) showing percentage of HMGA2 positive tumours from KP (n=29 tumours from 3 mice) or KPRb^TR/TR (n=37 tumours from 3 mice) mice that are positive or negative for FOXA2. Significance was determined by chi-square test (two-sided, p=1.1e-5).

(d) Histological analysis of KPRb^TR/TR metastases. H&E and IHC for NKX2–1, HMGA2 and FOXA2 on serial sections from representative metastases that are NKX2–1 positive or negative. Results are tabulated in the adjacent graph.

(e) IHC staining of KP and KPRb^TR/TR tumours for club (CC10) and neuroendocrine (synaptophysin) cell markers. For control and comparison, a synaptophysin positive small cell lung cancer from a p53^flox/flox; Rb^flox/flox; p130^flox/flox mouse model is shown⁴⁶.