MAPK3 and prostate cancer: In prostate cancer, p-ERK1/2 staining intensity in tumour cells declined with disease progression (Malik et al, 2002), and in small cell lung carcinomas, tumours with cytoplasmic expression of p-ERK had a better prognosis than p-ERK-negative cases, whereas no prognostic value was found for nuclear immunoreactivity (Blackhall et al, 2003).