Extended Data Fig. 3: RB deficiency is associated with low MAPK pathway signalling in mouse and human lung adenocarcinomas.

(a) H&E images of KP and KPRb^TR/TR tumours 8 weeks post tumour initiation. Corresponding IHC for ERK(P) (bottom).

(b) IHC for Ki67 in KP and KPRb^TR/TR tumours 8 and 14 weeks post tumour initiation.

(c) Quantification of Ki67 positive cells from (b). Symbols represent individual tumours (KP-8 week: n=9 tumours from 2 mice; KPRb^TR/TR-8 week: n=9 tumours from 2 mice; KP-14 week: n=31 tumours from 3 mice; KPRb^TR/TR-14 week: n=31 tumours from 3 mice). Significance was determined by two-sided unpaired t-test with Welch’s correction for 8 week (p=0.0034) and 14 week analyses (p=0.2686). Line indicates mean±SD.

(d) Plot showing the relationship of ERK(P) positive fraction versus Ki67 positive fraction in KP (n=15 tumours from 2 mice) and KPRb^TR/TR (n=16 tumours from 2 mice) tumours at 14 weeks after tumour initiation. Significance was determined by linear regression analysis (p=0.0376).

(e) Immunohistochemistry for RB depicting an RB-negative core (left) and an RB-positive core (right).

(f) Immunohistochemistry for p16 depicting a p16-negative core (left), a core with low staining (middle) and a core with high staining (right).

(g) Immunohistochemistry for RB(P)807/811 depicting two examples of cores with low expression (left), and high expression (right).

(h) Immunohistochemistry for ERK(P) depicting a core with an ERK(P) staining score of 0 (left), a score of 1 (middle-left), a score of 2 (middle-right), and a score of 3 (right).

Scale bars=100μM, inset images are magnified 5x further.