PTK2 and small cell lung carcinoma: Interestingly, the proportion of activated FAK compared with total FAK expression was significantly increased in SCLC as compared with NSCLC, as assessed by the ratio between mean phospho-FAK staining score and mean FAK staining score (0.025 ± 0.063 vs. 0.011 ± 0.014) (p < 0.01) (Figure 3C).