XENOGRAFT GROWTH AND HISTODIFFERENTIATION OF SQUAMOUS-CELL CARCINOMASOF THE PHARYNX AND LARYNX

The potential for growth in a xenogeneic host and the pattern of histo differentiation was examined in 56 human squamous cell carcinomas of t he pharynx and larynx transplanted to nude mice. Among these 56 transp lanted tumors, 13 of 36 primary and 12 of 20 metastatic tumors were fo und to be tumorigenic in nude mice. Eleven of 24 pharyngeal and 14 of 32 laryngeal tumors grew in nude mice. The dynamics of transplanted tu mor growth in the surrogate host rook place independent of the tumor g rade and site of tumor origin. Transplanted tumors exhibited a higher mitotic index compared with the original tumors. Each passage of a tum or line resulted in most of the xenograft tumors exhibiting an increas ed degree of differentiation without invasion of host tissues. No diff erence was observed between patients who engrafted tumors in the xenog raft model and those who did not with respect to tumor biology or clin ical findings, including survival.