乳腺导管原位癌免疫微环境的预后意义

　　肿瘤浸润淋巴细胞浸润于肿瘤周围微环境，其中包括各种亚型的T淋巴细胞、B淋巴细胞等。对于乳腺导管癌，不同亚型肿瘤浸润淋巴细胞的作用尚不明确。

　　2020年3月17日，英国癌症研究基金会《英国癌症杂志》在线发表英国诺丁汉大学、诺丁汉市立医院、埃及阿斯由特大学、澳大利亚彼得·麦卡伦癌症中心、墨尔本大学的研究报告，探讨了B淋巴细胞、T淋巴细胞、免疫检查点蛋白质表达对于乳腺导管原位癌的预后意义。

　　该研究对1990～2012年诺丁汉市立医院连续700例特征明确的导管原位癌患者进行长期随访，包括单纯导管原位癌患者508例、导管原位癌＋浸润癌混合患者192例，并对全部患者的B淋巴细胞标记CD20、T淋巴细胞标记CD3、辅助型T淋巴细胞标记CD4、杀伤型T淋巴细胞标记CD8、调节型T淋巴细胞标记FOXP3、免疫检查点蛋白质PD-1和PD-L1进行免疫组织化学染色，对其中58例患者的拷贝数量改变和TP53基因突变状态进行测定。

　　结果发现，对于单纯导管原位癌患者队列，CD3阳性淋巴细胞为主要的细胞亚型，而FOXP3阳性淋巴细胞最少。PD-L1主要表达于间质肿瘤浸润淋巴细胞。肿瘤浸润淋巴细胞亚型丰度较高与肿瘤分级较高、激素受体阴性、HER2阳性相关。TP53基因突变与基质CD3阳性、CD4阳性、FOXP3阳性细胞水平较高相关。

　　对于导管原位癌＋浸润癌混合患者队列，全部免疫细胞和检查点蛋白质基质浸润密度较高，除了CD4阳性细胞。基质PD-1是导管原位癌与浸润癌表达差异最大的蛋白质（Z=5.8，P<0.0001）。

　　肿瘤浸润淋巴细胞、间质FOXP3和PD-L1密度较高是导管原位癌复发的不良预后因素，而肿瘤浸润淋巴细胞密度较高是全部复发（风险比：7.0，P=0.024）和浸润复发（风险比：2.1，P=0.029）的独立影响因素。

　　因此，该研究结果表明，免疫抑制蛋白是高风险导管原位癌和疾病进展的潜在标志。单纯导管原位癌、导管原位癌＋浸润癌、浸润癌的基质和肿瘤浸润淋巴细胞不同组成对于其预后意义可能发挥潜在影响，并与基因组潜在不稳定性相关。对肿瘤浸润淋巴细胞进行整体测定，有助于导管原位癌免疫微环境分析。

Br J Cancer. 2020 Mar 17. [Epub ahead of print]

The prognostic significance of immune microenvironment in breast ductal carcinoma in situ.

Michael S. Toss, Asima Abidi, Dorothea Lesche, Chitra Joseph, Sakshi Mahale, Hugo Saunders, Tanjina Kader, Islam M. Miligy, Andrew R. Green, Kylie L. Gorringe, Emad A. Rakha.

The University of Nottingham, Nottingham City Hospital, Nottingham, UK; Assiut University, Assiut, Egypt; Peter MacCallum Cancer Centre, Melbourne, Australia; University of Melbourne, Parkville, Australia.

BACKGROUND: The role of different subtypes of tumour infiltrating lymphocytes (TILs) in breast ductal carcinoma in situ (DCIS) is still poorly defined. This study aimed to assess the prognostic significance of B and T lymphocytes and immune checkpoint proteins expression in DCIS.

METHODS: A well characterised DCIS cohort (n=700) with long-term follow-up comprising pure DCIS (n=508) and DCIS mixed with invasive carcinoma (IBC; n=192) were stained immunohistochemically for CD20, CD3, CD4, CD8, FOXP3, PD1 and PDL1. Copy number variation and TP53 mutation status were assessed in a subset of cases (n=58).

RESULTS: CD3+ lymphocytes were the predominant cell subtype in the pure DCIS cohort, while FOXP3 showed the lowest levels. PDL1 expression was mainly seen in the stromal TILs. Higher abundance of TILs subtypes was associated with higher tumour grade, hormone receptor negativity and HER2 positivity. Mutant TP53 variants were associated with higher levels of stromal CD3+, CD4+ and FOXP3+ cells. DCIS coexisting with invasive carcinoma harboured denser stromal infiltrates of all immune cells and checkpoint proteins apart from CD4+ cells. Stromal PD1 was the most differentially expressed protein between DCIS and invasive carcinoma (Z=5.8, p<0.0001). Dense TILs, stromal FOXP3 and PDL1 were poor prognostic factors for DCIS recurrence, while dense TILs were independently associated with poor outcome for all recurrences (HR=7.0; p=0.024), and invasive recurrence (HR=2.1; p=0.029).

CONCLUSIONS: Immunosuppressive proteins are potential markers for high risk DCIS and disease progression. Different stromal and intratumoural lymphocyte composition between pure DCIS, DCIS associated with IBC and invasive carcinoma play a potential role in their prognostic significance and related to the underlying genomic instability. Assessment of overall TILs provides a promising tool for evaluation of the DCIS immune microenvironment.

DOI: 10.1038/s41416-020-0797-7