Table I.

The majority of STAT6−/− mice are metastasis free after surgical removal of the primary mammary tumora

OrganBALB/cbSTAT6−/−c
Mice with metastasis (%)dMetastatic cells/organdMice with metastasis (%)dMetastatic cells/organd
Lung92.51228− 2.8× 105405–3383e
(6× 104± 9.2× 104)(1158± 1315)
Bone marrow541–61200
(94± 176)
Liver925− 1.9× 1041550–530
(3431± 6164)(214± 186)
  • a BALB/c and STAT6−/− mice were inoculated with 7000 4T1 cells in the mammary gland. Two to 3 wk later, the primary tumors were surgically removed. On days 42–45 after initial 4T1 inoculation, mice were sacrificed, and the lungs, liver, and bone marrow were assayed by the clonogenic assay for the number of metastatic 4T1 cells. Average diameter of primary BALB/c vs STAT6−/− tumors at the time of surgery: 4.99 mm ± 1.42 vs 4.38 ± 1.31, respectively.

  • b Thirteen mice per group.

  • c Twenty mice per group.

  • d Number of metastatic cells determined by the clonogenic assay. Top number is the range of metastatic cells; number in parentheses is the average number of metastatic cells ± SD. Calculation includes only those mice with metastasis.

  • e A statistically significant difference between the STAT6−/− and BALB/c values (p ≤ 0.05) for the number of metastatic cells per organ.