Figure 4.
Genetic progression model of head and neck tumorigenesis. Clinical and histologic progression from simple squamous hyperplasia through the advancing stages of squamous dysplasia to invasive squamous cell carcinoma is driven by the progressive accumulation of genetic alterations. Some alterations, such as loss of heterozygosity (LOH) at chromosomal loci 3p and 9p, occur earlier in this sequence than do other alterations. Figure illustrated by Robert Morreale, CMI and contributed by Joseph Califano, MD. Reproduced with permission from New England Journal of Medicine.