IGHG1 and neoplasm: Reclustering revealed 11 distinct subclusters (Fig. 3h), of which nine were enriched in tumor and interface zones and designated as plasma B cells (clusters 2 and 10, IGHG1 +), follicular B cells (clusters 0, 3, 6, 8 and 9, MS4A1 +), immature B cells (cluster 7, IL7R +) and mast cells (cluster 5, TPSAB1 +) (Fig. 3i).