The proinflammatory cytokine tumor necrosis factor-alpha (TNF-α) inhibits normal keratinocytes proliferation. However, many human papillomavirus (HPV)-immortalized or transformed cell lines are resistant to TNF-α antiproliferative effect. The present study analyzes the effects of TNF-α on organotypic cultures of primary human keratinocytes (PHKs) that express HPV-18 oncogenes. Raft cultures prepared with PHKs acutely transfected with HPV-18 whole genome or infected with recombinant retroviruses containing only E6/E7 or E7 were treated with 2 nM TNF-α. While BrdU incorporation into basal/parabasal cells of normal PHKs cultures was markedly inhibited by TNF-α cultures transfected with HPV-18 whole genome showed proliferation in all cell strata. Furthermore, BrdU incorporation into cultures expressing E6/E7 or E7 was not significantly reduced, indicating that E7 alone confers partial resistance to TNF-α. Besides, TNF-α treatment did not alter p16 ink4a, p21 cip1, p27 kip1, or cyclin E levels, but did reduce cyclin A and PCNA levels in sensitive cells. © 2004 Elsevier Inc. All rights reserved.