Table 1. Presence of HPV gene sequences in DNA extracted from 50 human breast tumours.

Correlations of the presence of HPVa with	Spearman's correlation coefficientb	Two-tailed significancec
Tumour grade	0.127	0.378 NS
Patient's mortalityd	−0.107	0.461 NS
ER-positive tumoure	0.132	0.364 NS
PR-positive tumourf	0.104	0.479 NS
ERBg receptor	0.089	0.591 NS
p53h expression	0.090	0.533 NS
p53i mutation	−0.103	0.478 NS

^aSamples which have HPV sequences identified at least once by PCR are included in the statistical analysis and considered as HPV positive.

^bSpearman's rank order correlation for nonparametric data. The correlation coefficient ranges from −1 to 1 for perfect correlations.

^cThe significance is two-tailed. NS=not significant at 95% level.

^dMortality=death due to recurrence of breast cancer (eight patients).

^eER=oestrogen receptor positively expressed in at least 5% of cancer cells.

^fPR=progesterone receptor expressed in at least 5% of cancer cells.

^gERB=ERB receptor expressed in the cytoplasm of cancer cells.

^hp53 expression=p53 protein expressed in at least 5% of cancer cells.

ⁱp53 mut=p53 mutations identified in cancer cells.

Correlations with grade, survival, ER, PR, ERB-2, P53 expression and p53 mutations.