HPV genotyping was performed on cervix biopsies by polymerase chain reaction using SPF-10 broad-spectrum primers, followed by deoxyribonucleic acid enzyme immunoassay and genotyping by reverse hybridization line probe assay (LiPA25) (version 1) (n=202). PapilloCheck and quantitative reverse transcription-polymerase chain reaction were used to genotype cervix cancer cell lines (n=16). Local progression-free survival after radiation therapy alone was assessed using log-rank and Cox proportionate hazard analyses. Intrinsic radiosensitivity was measured as surviving fraction at 2 Gy (SF2) using clonogenic assays.
Of the 202 tumors, 107 (53.0 % ) were positive for HPV16, 29 (14.4 % ) for HPV18, 9 (4.5 % ) for HPV45, 23 (11.4 % ) for other HPV genotypes, and 22 (10.9 % ) were negative; 11 (5.5 % ) contained multiple genotypes, and 1 tumor was HPV X (0.5 % ). In 148 patients with outcome data, those with HPV¦Á9-positive tumors had better local progression-free survival compared with ¦Á7 patients in univariate (P<.004) and multivariate (hazard ratio 1.54, 95 % confidence interval 1.11-1.76, P=.021) analyses. There was no difference in the median SF2 of ¦Á9 and ¦Á7 cervical tumors (n=63). In the cell lines, 9 were ¦Á7 and 4 ¦Á9 positive and 3 negative. There was no difference in SF2 between ¦Á9 and ¦Á7 cell lines (n=14).
The reduced radioresponsiveness of ¦Á7 cervical tumors is not related to intrinsic radiosensitivity.