The pregnancy-associated alpha 2-glycoprotein (alpha 2-PAG). A tumour marker?

Long-term studies of alpha 2-PAG in sera of patients with breast cancer, bronchial carcinoma, gynaecological carcinoma, melanoma and laryngeal carcinoma have proved that alpha 2-PAG is a possible laboratory parameter for the assessment of recurrence of tumour and metastasis. The results published for trophoblastic tumour and gastrointestinal carcinoma are still divergent. Because of the large individual range of alpha 2-PAG concentrations and the widely differing alpha 2-PAG levels in men and women single determinations of this protein are without value. A detailed classification of the pathological mechanisms to which these proteins are submitted is still missing and consequently we have no fundamental knowledge of diseases that apart from pregnancy and neoplasia lead to changes in the physiological alpha 2-PAG serum concentration.