The analysis of HE-stained sections derived from tumours or relevant areas of inoculation showed that the CAL-27 cells formed squamous carcinoma with heteromorphism, but PBS, SHED-ori P4, or SHED-Bmi1-EGFP P40 did not show any signs of tumour growth (Figure 4(c)). Here, BMI1 is linked to squamous cell carcinoma.