Stackpole C W
Department of Pathology, New York Medical College, Valhalla.
Invasion Metastasis. 1990;10(5):267-80.
Spontaneous metastasis of subcutaneous B16 melanoma transplants proceeds in two distinct stages: initially to the lungs, and secondarily, following tumor removal, from established lung metastases to extrapulmonary systemic sites. Coincident with extrapulmonary metastasis, there is a dramatic amplification of visible lung metastases, with death generally resulting from extensive lung metastasis. The progression of lung metastasis, and lung colonization initiated by intravenous injection of tumor cells, was investigated using B16 melanoma clone G3.12. Analysis of the growth of invisible metastases in organ culture explants of lung revealed that tumors continually disseminated relatively small numbers of lung metastases after reaching a size of about 6 mm in diameter. However, most terminal-stage lung metastases, along with all extrapulmonary metastases, apparently arise from a secondary spread of tumor cells from tumor-derived lung metastases 1-2 mm in size. Individual lung colonies, initiated with G3.12 cells bound to single microbeads, also disseminated large numbers of secondary lung colonies, as well as extrapulmonary colonies, at a 1- to 2-mm size. The mechanism for intrapulmonary spread of secondary metastases and colonies is unclear, but the consequence appears to be a secondary stage of intrapulmonary and extrapulmonary metastasis with selection for tumor cells with rapid growth rates.
皮下接种的B16黑色素瘤自发转移过程分为两个不同阶段：首先转移至肺部，其次，在肿瘤切除后，已形成的肺转移灶会转移至肺外的全身部位。在发生肺外转移的同时，可见的肺转移灶会急剧增加，死亡通常是由广泛的肺转移所致。利用B16黑色素瘤克隆G3.12研究了肺转移的进展以及静脉注射肿瘤细胞引发的肺定植情况。对肺器官培养外植体中不可见转移灶生长情况的分析表明，肿瘤在直径达到约6 mm后会持续播散相对少量的肺转移灶。然而，大多数终末期肺转移灶以及所有肺外转移灶显然都源自大小为1 - 2 mm的肿瘤源性肺转移灶中的肿瘤细胞的二次扩散。用与单个微珠结合的G3.12细胞启动的单个肺集落也会播散大量大小为1 - 2 mm的继发性肺集落以及肺外集落。继发性转移灶和集落在肺内扩散的机制尚不清楚，但结果似乎是肺内和肺外转移的第二阶段，且选择了生长速度快的肿瘤细胞。
