Meta-analysis for all groups of leptin level.

BC;breast cancer; HC: healthy control; Pre-BC: premenopausal breast cancer; Pre-HC: premenopausal healthy control; Post-BC: postmenopausal breast cancer; Post-HC: postmenopausal healthy control; BBC;benign breast controls; Pre-BBC;premenopausal benign breast controls;Post-BBC: postmenopausal benign breast controls; LN+: lymph node metastasis positive cases; LN-: lymph node metastasis negative controls.BC：乳腺癌（breast cancer）；HC：健康对照（healthy control）；Pre-BC：绝经前乳腺癌（premenopausal breast cancer）；Pre-HC：绝经前健康对照（premenopausal healthy control）；Post-BC：绝经后乳腺癌（postmenopausal breast cancer）；Post-HC：绝经后健康对照（postmenopausal healthy control）；BBC：乳腺良性对照（benign breast controls）；Pre-BBC：绝经前乳腺良性对照（premenopausal benign breast controls）；Post-BBC：绝经后乳腺良性对照（postmenopausal benign breast controls）；LN+：淋巴结转移阳性病例（lymph node metastasis positive cases）；LN-：淋巴结转移阴性对照（lymph node metastasis negative controls）