Lymphatic vessels play a crucial role in a variety of human cancers, since invasion of lymphatic vessels by tumor cells and subsequent development of lymph node metastases significantly influences prognosis of cancer patients and therefore represent an integral part of tumor staging. Recent evidence on the important influence of lymphangiogenetic growth factors on intralymphatic cancer growth and metastasis raises hopes that lymphatic vessels and factors inducing their growth could serve as an additional target for tumor therapy. Nevertheless, in contrast to blood vessel angiogenesis, the mechanisms of new lymphatic vessel formation in human cancers, ie lymphangiogenesis, are still relatively unclear. In addition, only little data exist so far on the quantification and impact of this lymphangiogenesis, evident by lymphatic microvessel density (LMVD), on the prognosis of cancer patients. With expectation of possible anti-lymphangiogenic therapies, this review focuses on the mechanisms of lymphangiogenesis in general, and especially on the role of lymphatic vessels in gynecological and breast cancer, which are the so far most detailed investigated malignancies with regard to lymphangiogenesis.