HOXB13 and invasive breast carcinoma: Of the 32 invasive breast carcinomas tested (15 cases of stage I tumors, nine cases of stage II tumors and eight cases of stage III tumors) 29 displayed higher levels of methylation relative to their matching controls within the HOXB13 element (91%), whereas the HNF1B CpG island was methylated in 21 tumor samples (66%) (partial COBRA data are shown in Figure 4).