Immunohistochemical localization of alpha-lactalbumin in human breast cancer tissue.

One hundred and eleven formalin-fixed breast cancer tissue samples were examined for the presence of alpha-lactalbumin using our polyclonal antibodies to this specific milk protein. Alpha-lactalbumin was shown to be present in 67 tumor samples (60%), in 15% of cases the occurrence of alpha-lactalbumin was questionable. No relationship was found between alpha-lactalbumin positivity and the histological type of the tumor, differentiation grading, type of invasivity, or stromal reactivity. Disease progression occurred in an equal number of patients with tumors either alpha-lactalbumin positive or negative. However, negativity was often connected with a disease-free interval shorter than 24 months after primary operation.