The relationship between primary tumour-infiltrating immune cells and immune activation status of tumour draining lymph nodes in oesophageal cancer patients – results from the UK MRC OE02 trial

Patients with resectable oesophageal cancer have a 5-year overall survival of 25-47%. One of the most robust prognostic factors is the lymph node (LN) status. The regional tumour draining LNs (TDLN) play an important role in the host anti-tumour immune response. We demonstrated previously that the microarchitecture (number of germinal centres, sinus histiocytosis, paracortical expansion) changes after chemotherapy in tumour negative and positive LNs (LNneg and LNpos) and predicts overall survival. It is currently unknown whether microarchitectural features of TDLN are associated with the presence of T-cells or macrophages in the primary tumour. We hypothesized that patients with immune activated TDLN e.g. with follicular or paracortical hyperplasia have increased CD3-positive or CD8-positive T-cells and decreased FOXP3-positive Tregs in the primary tumour.

CD3, CD8, CD68 and FOXP3 immunohistochemistry was performed on tissue microarrays constructed from the primary tumour resection of 328 patients. Immune reactivity was quantified using image analysis. LN microarchitecture data was available for 207 of 328 patients (98 chemotherapy and surgery (CS), 109 surgery alone patients (S)). 49 patients were classified as (y)pN0. LN microarchitecture data was generated previously whereby the area of the different histological components (lymphocytes outside germinal centres, germinal centres, histiocytes, tumour, vessels, other) of the largest LNpos and largest LNneg per patient was morphometrically quantified and expressed as %LN area. LN microarchitecture data were dichotomized at the median. The relationship between individual LNpos and LNneg microarchitectural features (high versus low) and CD3, CD8, CD45, CD68 and FOXP3 positive immune cells was analyzed per treatment arm and by lymph node status.

Paracortical hyperplasia (high %LNarea with lymphocytes outside germinal centres) or follicular hyperplasia (high %LNarea with germinal centres) in the LNneg was related to a decreased number of FOXP3-positive T-cells in the primary tumour in CS patients (all p-values < 0.05). When comparing ypN1 with ypN0 patients, the above relationship was only seen in ypN1 CS patients (p < 0.05). There was no relationship between CD3, CD8, CD45, CD68 and FOXP3 in the primary tumour and LNneg microarchitectural features in S patients. There was no relationship between LNpos microarchitectural features and any of the markers neither in S patients nor in CS patients.

This is the first study to associate microarchitectural features of tumour draining lymph node with primary tumour infiltrating lymphocytes or macrophages in oesophageal cancer patients treated with or without neoadjuvant chemotherapy. Our findings seem to suggest that the immune activation status of LNneg might affect number of immune inhibitory FOXP3-positive Tregs in the primary tumour after chemotherapy. Interestingly, with exception of FOXP3-positive Tregs, there seems to be no relationship between immune cell types in the primary tumour and immune activation status of the TDLN. In order to completely characterize patients’ anti-tumour immune landscape, it might be necessary to analyze both microarchitectural features of the tumour draining lymph node and tumour infiltrating immune cells. These results need to be confirmed in a larger series and underlying biological mechanisms for the observed findings need to be further investigated.

UK MRC OE02 trial.

The authors.

Cancer Research UK.

D. Cunningham: Advisory / Consultancy: OVIBIO on Scientific Advisory Board; Research grant / Funding (institution): AstraZeneca / MedImmune, Celgene, Bayer, 4SC, Eli Lilly, Clovis, Natera, Roche, Leap. D. Magee: Shareholder / Stockholder / Stock options: HeteroGenius Limited, HeteroGenius Limited, HeteroGenius Limited; Licensing / Royalties: HeteroGenius Limited, HeteroGenius Limited, HeteroGenius Limited; Full / Part-time employment: HeteroGenius Limited, HeteroGenius Limited, HeteroGenius Limited; Officer / Board of Directors: HeteroGenius Limited, HeteroGenius Limited, HeteroGenius Limited. All other authors have declared no conflicts of interest.