Immunoglobulin G (IgG) levels in breast tumor cytosols.

Immunonephelometer investigation of specific proteins revealed a difference in levels of immunoglobulin G (IgG) found in the cytosol of estrogen receptor (ER) rich and estrogen receptor poor tumor tissue. Cytosols from estrogen receptor poor tumors had a significantly higher level of IgG than those from estrogen receptor rich tissues. The relationship between progesterone receptor levels and IgG was not as significant as that observed between ER levels and IgG. Other specific proteins did not correlate with either estrogen receptor levels or progesterone levels.