Biological characterization of subgroups of squamous cell lung carcinomas.

Recently, Pezzella et al. (Am. J. Pathol., 1997, 151: 1417-1423, 1997) reported on a subgroup of non-small cell lung carcinomas that had no morphological evidence of neoangiogenesis but appeared to grow and were highly aggressive. In this investigation, we subdivided 87 squamous cell lung carcinomas into four subgroups according to angiogenesis (low and high vessel density) and tumor growth (low and high tumor cell proliferation). The aim was to find differences, if any, in the angiogenic status and clinical behavior between these subgroups. We identified a group of tumors with low angiogenesis and high tumor cell proliferation that was characterized by high expression of vascular endothelial growth factor, low expression of basic fibroblast growth factor, reduced apoptosis, increased incidence of metastases, and short survival times. These data show that even squamous cell lung carcinomas are a heterogeneous group of tumors that can be subdivided in tumors with different biological properties and different clinical behaviors.