Squamous cell carcinoma of the head & neck and cervix: Overlap and distinctions

The practice of medicine would be easier if the mathematical law of identity was as readily applicable in the biologic world. One illness is not the same as another. Within a single illness, cancer, for example, the spectrum of clinical significance ranges from none (low-volume, low-grade prostate carcinoma) to dire (glioblastoma multiforme, an aggressive form of brain cancer). Much of the success of medical research came about through attempts to progressively subclassify diseases into more uniform groups to facilitate their study. In this chapter we focus on a single common histologic tumor type, squamous cell carcinoma, noting similarities and important differences that occur depending on origin in either the head & neck or the uterine cervix. Although smoking is the primary risk factor for head and neck carcinoma, and persistent infection with high-risk variants of the human papillomavirus (HPV) is essential for the development of cervical cancer, the story is more complex. Subsets of head & neck cancers have recently been linked to HPV infection, and epidemiologic studies consistently link smoking with cervical carcinoma. Distinct differences are beginning to emerge at the molecular level between smoking- and HPV-related squamous carcinoma. These new insights may bring us closer to telling when a rose actually is a rose.