Some etio-pathogenetic factors in laryngeal carcinogenesis

Chemical influences, mainly heavy tobacco smoking, chewing snuff, excessive alcohol consumption, and some occupational hazards, are known to be important etiologic factors in laryngeal carcinogenesis. The synergistic or cooperative interaction of human papilloma virus (HPV) infection with these chemical factors are serious considerations in the development of laryngeal carcinoma. With the development during the last decade of Southern blot hybridization and polymerase chain reaction (PCR), extensive and comprehensive studies have been conducted to determine the presence and biological (etiologic) significance of HPV. Developed cancer, as well as juvenile and adult multiple and single papilloma of the larynx, have been the subject of clinical and molecular-pathological investigation. Our previous study showed that cancer may develop on the basis of leukoplakia and adult-onset papilloma. Extensive kilocytes, an indication of HPV infection, can be seen by histological examination in papillomas and carcinoma. Literary data suggest that in laryngeal squamous cell carcinoma, including varicoses carcinoma, HPV 16, HPV 18, and HPV 33 DNA have been detected. Both in juvenile and adult-onset respiratory papillomatosis, patients could have either HPV type 6 or 11 DNA sequences. Molecular biological and PCR studies indicate that HPV may play an etiologic role in the development of human malignancies of the upper aerodigestive tract and uterine (cervical) origin. However, evidence that unequivocally links HPV infection with laryngeal squamous cell carcinoma is still lacking. In laryngeal cancer, p53 abnormalities are related to smoking-induced mutagenesis rather than HPV. Studies have postulated an interaction between HPV infection and chemical carcinogens and have concluded that HPV possibly are co-adjuvants during the multistage process of neoplastic transformation.