*3.4. Association of HPV 16 Sub-Lineages with Demographic and Clinical Variables*

From the 119 anal cancers, four samples did not contain vital status information and were not included in the analysis. Due to the dominance of the A1 sub-lineage, the logistic analysis and odds ratio analysis were performed based on the presence or absence of the HPV 16 sub-lineage A1.

No significant differences in A1 positivity with sex, age, response to treatment, stage or vital status were observed. This observation was consistent for the adjusted analysis (Table 3).


**Table 3.** Influence of A1 sub-lineage presence stratified by demographic and clinical variables. The comparator for the odds ratio (univariate and adjusted) is A1 absence.
