Table 1.

HERV-K env mRNA and Protein Expression in Breast Tissues from Chinese women

Sample description	Negative		Positive		% Positive	Total	P value (χ2 test)
HERV-K mRNA expression assessed by RT-PCR
Breast cancer tissue	12		28		70.0	40
Uninvolved breast tissue	32		8		20.0	40
Normal breast tissue	40		0		0.0	40	<0.0001a
Sample description	–	+	++	+++	% Positive	Total	P value (χ2 test)
HERV-K protein expression assessed by IHC
Benign tissues	18	12	0	0	40.0	30
Cancer tissues	15	11	25	59	86.4	110	<0.0001b

^aComparison of the positive expression rate of the 3 groups using contingency table analysis χ² (and Fisher’s exact) test by GraphPad Prism 5.

^bComparison of the positive expression rate of the 2 groups using contingency table analysis χ² (and Fisher’s exact) test by GraphPad Prism 5.