['In individual patients with squamous cell carcinoma of the head and neck (SCCHN), established prognostic factors do not satisfactorily predict clinical outcome. Although the karyotype is an independent prognostic factor in certain hematologic malignancies and solid tumors, no data have been reported concerning the possible relationship between chromosomal abnormalities and clinical outcome in patients with SCCHN:', 'In 116 cases of primary SCCHN, short term cultures were analyzed cytogenetically during 1987 through 1991, the karyotypes were divided into four groups: k1, normal (n = 35); k2, numeric changes only (n = 31); k3, simple structural abnormalities (n = 27); and k4, complex karyotypes (n = 23). The patients were followed for at least 18 months after diagnosis or until death.', 'The 2-year survival rate was lower in the k4 subgroup (35%) than in the k1, k2, and k3 subgroups taken together (61%), both in the series as a whole (P = 0.02), and in the largest tumor site subgroup, laryngeal squamous cell carcinoma (n = 32), (P = 0.04). The most prevalent breakpoint was in chromosome band 11q13, occurring in 11 tumors, 10 of which belonged to the k4-subgroup. The 2-year survival rate was lower for patients with 11q13 rearrangements (20%) than for those without (60%), both in the series as a whole (P = 0.001), and in the k4-subgroup (P = 0.02).'] Are chromosomal abnormalities involving 11q13 associated with poor prognosis in patients with squamous cell carcinoma of the head and neck?