Figure 1

Normal bronchial mucosa, atypical adenomatous hyperplasia (AAH), squamous dysplasia and invasive squamous carcinoma have been stained for various markers. The first column shows hematoxylin and eosin (H&E) tissue staining. The picture of AAH shows low (40×) and high (400×, inset) power images. The H&E staining of squamous dysplasia shows relatively normal mucosa on the left of the image and severe dysplasia on the right. In severe dysplasia, there is considerable cellular pleiomorphism, coarse uneven chromatin, and little cell maturation. Vertical nuclei and mitotic figures are present in the lower two thirds of the mucosa. In invasive carcinoma the cytological aberration is extreme, mitoses occur at all levels of the mucosa, and maturation is absent. The second column shows staining for the proliferation marker, Ki-67, in the various lesions. Ki-67 is essentially negative in normal tissue. The images show increased Ki-67 in AAH, with a further increase in squamous dysplasia and carcinoma. In the third column, p53 is not observed in the normal bronchial mucosa or in AAH, but is increased in both squamous dysplasia and squamous carcinoma. In the fourth column, p21 (p53-inducible cyclin dependent kinase inhibitor) is increased only in squamous carcinoma, but not in AAH or normal bronchial mucosa.