Estrogen receptor analysis on needle aspirates from human mammary carcinoma

Immediately after mastectomy, estrogen receptor concentration was measured in fine needle aspirates and in histologic tissue specimens from 13 human breast carcinomas. Fine needle aspirates were shown to contain enough material for receptor analysis when the sensitive method of isoelectric focusing in slabs of polyacrylamide gel was used for receptor determination. Aspirations with two different needles (outer diameter 0.7 and 1.4 mm) from each tumor yielded highly correlated receptor values (r = 0.97, p less than 0.0001). There was also a highly significant correlation (r = 0.91, p less than 0.0001) between the receptor content in needle aspirates and in tissue specimens from the same tumor.