Department of Histopathology, Royal Surrey County Hospital, Guilford, UK.
J Clin Pathol. 2011 Dec;64(12):1108-11. doi: 10.1136/jclinpath-2011-200242. Epub 2011 Sep 6.
Some views on sentinel nodes for melanoma seem to cast doubt on the relevance of micrometastases in the sentinel nodes of patients with melanoma, suggesting that small metastases or isolated tumour cells can be ignored. Tumour dormancy has been proposed for their postulated lack of progression. The implication of the argument seems to be that minute metastases are inactive and therefore non-threatening, whereas larger ones are proliferative and therefore have aggressive potential.
54 sentinel lymph nodes were studied with histologically identified micrometastatic melanoma using the protocol accepted by the European Organisation for Research and Treatment of Cancer melanoma group. These were studied with respect to metastasis size and by use of immunohistochemical markers of proliferation (MIB-1) and dormancy (p16).
The authors have demonstrated no correlation between the size of metastases and their proliferative activity. Very small metastases may not show proliferative activity, but this may be a reflection of the small number of assessable cells rather than a genuine reflection of the tumoural characteristics. Furthermore, the minute size of some of these metastases resulted in no residual tumour being present in adjacent sections. Where further sections did show more tumour, these small metastases were invariably p16 negative, suggesting dormancy was not the explanation for the lack of measurable proliferation. Occasionally, larger metastases, clearly not clinically insignificant, showed no proliferative activity presumably, considering their size, a transient phenomenon.
These findings suggest that variable phases in proliferation occur in metastases, and no conclusion of clinical insignificance can be made on the basis of small size.
一些关于黑色素瘤前哨淋巴结的观点似乎对黑色素瘤患者前哨淋巴结中微转移的相关性提出了质疑，表明可以忽略小的转移或孤立肿瘤细胞。肿瘤休眠被认为是其缺乏进展的原因。这一论点的含义似乎是，微小的转移是不活跃的，因此没有威胁性，而较大的转移是增殖性的，因此具有潜在的侵袭性。
使用欧洲癌症研究与治疗组织黑色素瘤小组认可的方案，对 54 个经组织学证实有黑色素瘤微转移的前哨淋巴结进行了研究。研究了转移的大小，并使用增殖（MIB-1）和休眠（p16）的免疫组织化学标志物进行了研究。
作者没有发现转移的大小与其增殖活性之间的相关性。非常小的转移可能没有增殖活性，但这可能是由于可评估细胞的数量较少，而不是肿瘤特征的真实反映。此外，这些微小转移中的一些体积非常小，以至于在相邻的切片中没有残留的肿瘤。在进一步的切片中确实显示出更多的肿瘤时，这些微小的转移总是 p16 阴性，这表明休眠不是缺乏可测量增殖的原因。偶尔，更大的转移，显然没有临床意义，也没有表现出增殖活性，也许考虑到它们的大小，这是一种短暂的现象。
这些发现表明，转移中存在增殖的不同阶段，不能仅根据肿瘤的大小来判断其是否具有临床意义。
