Subtype-Based Prognostic Analysis of Cell-in-Cell Structures in Early Breast Cancer

Abstract

Though current pathological methods are greatly improved, they provide rather limited functional information. Cell-in-cell structures (CICs), arising from active cell–cell interaction, are functional surrogates of complicated cell behaviors within heterogeneous cancers. In light of this, we performed the subtype-based CIC profiling in human breast cancers by the “EML” multiplex staining method, and accessed their values as prognostic factors by Cox univariate, multivariate, and nomogram analysis. CICs were detected in cancer specimens but not in normal breast tissues. A total of five types of CICs were identified with one homotypic subtype (91%) and four heterotypic subtypes (9%). Overall CICs (oCICs) significantly associated with patient overall survival (OS) (P = 0.011) as an independent protective factor (HR = 0.423, 95% CI, 0.227–0.785; P = 0.006). Remarkably, three CICs subtypes (TiT, TiM, and MiT) were also independent prognostic factors. Among them, higher TiT, from homotypic cannibalism between tumor cells, predicted longer patient survival (HR = 0.529, 95% CI, 0.288–0.973; P = 0.04) in a way similar to that of oCICs and that (HR = 0.524, 95% CI, 0.286–0.962; P = 0.037) of heterotypic TiM (tumor cell inside macrophage); conversely, the presence of MiT (macrophage inside tumor cell) predicted a death hazard of 2.608 (95% CI, 1.344–5.063; P = 0.05). Moreover, each CIC subtype tended to preferentially affect different categories of breast cancer, with TiT (P < 0.0001) and oCICs (P = 0.008) targeting luminal B (Her2+), TiM (P = 0.011) targeting HR− (Her2+/HR− and TNBC), and MiT targeting luminal A (P = 0.017) and luminal B (Her−) (P = 0.006). Furthermore, nomogram analysis suggested that CICs impacted patient outcomes in contributions comparable (for oCICs, TiT, and TiM), or even superior (for MiT), to TNM stage and breast cancer subtype, and incorporating CICs improved nomogram performance. Together, we propose CICs profiling as a valuable way for prognostic analysis of breast cancer and that CICs and their subtypes, such as MiT, may serve as a type of novel functional markers assisting clinical practices.

High Frequency of Cell-in-Cell Formation in Heterogeneous Human Breast Cancer Tissue in a Patient With Poor Prognosis: A Case Report and Literature Review

“…Durgan et al (22), and our unpublished work as well, identified cell division as a potent inducer of entotic CIC formation, the mechanism might also work in this case as the tumor cells are undergoing active division as indicated by >70% Ki-67 positivity. A review of the limited literature on CIC formation in breast cancer (Table 1) showed that CIC structures were also frequently associated with active cell proliferation (3,22,24) and, to an extent, cellular heterogeneity (15,16,24,25); and the frequencies of CIC structure, although difficult to compare due to the different types of calculation, span a wide range from presence (24,25,27) to 6% in this study.…”

“…Cell cannibalism is a unique pathological phenomenon that has been observed in various types of human tumors, including breast cancer (1). Cannibalistic cells typically form cellin-cell (CIC) structures, characterized by enclosure of cells by another one, and this affects patient prognosis (2,3). CIC structures have not only been found in human tumors but also in animal tumors (4), suggesting that CIC is a general malignant phenomenon across species.…”

Role of Heterotypic Neutrophil-in-Tumor Structure in the Prognosis of Patients With Buccal Mucosa Squamous Cell Carcinoma

“…Cell-in-cell (CIC) is an evolutionarily conserved cytobiological phenomenon ( 1 , 2 ), which was first reported 150 years ago by a German scholar ( 3 ). It refers to the presence of one or more living cells within another living one and has ever since been found in varieties of tumors tissues, such as breast carcinoma ( 4 , 5 ), pancreatic ductal adenocarcinoma ( 6 ), and head and neck squamous cell carcinoma (HNSCC) ( 7 ) and the like. CIC has two typical forms: one is homotypic CIC, and the other is heterotypic CIC, with the latter often occurring between tumor cells and immune cells that include neutrophils ( 8 ).…”

Cell-in-cell phenomenon associates with aggressive characteristics and cancer-related mortality in early oral tongue cancer

“…The clinical significance of cannibalistic cell-in-cell structures has been reported in many cancers as an adverse prognostic feature [16,19,20]. Cellular cannibalism (i.e.…”

“…It is noteworthy that the cell-in-cell structure has been wellknown for decades among pathologists, but its clinical significance has remained neglected. Only recent research has emphasized the significance of the cell-in-cell phenomenon in the behavior of many cancers [15][16][17]. However, the clinical relevance of cell-in-cell has not been well-studied in many cancers of the head and neck region including early OTSCC.…”