We found that E6 expression is correlated with Id-1 overexpression in 94.25% of invasive breast cancer samples as opposed to 30.76% of in situ cancer tissues (Table 4 and Figure 1); whereas we presume that these in situ breast carcinomas, which are HPV-positive, will ultimately progress into invasive carcinomas under the effect of these HPVs, as they are already intermediate to high nuclear grade. Here, ID1 is linked to breast carcinoma.