LAUSR

To the Editor, I wish to congratulate Khader et al. for their article in which they investigated the association between delay in surgery and axillary upstaging of clinically node‐negative breast cancer patients. Patients diagnosed with cN0 BC undergoing surgery with sentinel lymph node biopsy were divided into four groups based on time intervals between diagnosis and surgery (<4, 4–8, 8–12, and >12 weeks). They reported that delay in BC surgery in cN0 patients was associated with an increased likelihood of axillary upstaging and decreased survival. In the subgroups of patients by hormone receptor status, the correlation between axillary upstaging and delay in surgery was only observed in the ER‐positive subgroup. There was no observed association between a delay in surgery and nodal positivity in the ER‐negative Her2 negative subgroups‐triple negative breast cancer (TNBC). Luminal types tend to have more frequent lymph node metastasis than HER2 or TNBC. The reason for this difference in the extent of nodal metastasis according to subtype is not clear. The expression of molecules that drive tumor growth and lymphatic metastasis may play a role. As estrogen was reported to downregulate the expression of VEGF, its level of expression in luminal types was relatively low, while HER2 and TNBC had higher expression of VEGF. TNBC has higher microvascular density and higher expression of VEGF. We studied capillary and lymphatic invasion in tumors of patients with TNBC. To differentiate the capillary invasion and lymphovascular invasion, the anti‐ human CD34 and anti‐human D2‐40 antibodies were used. Anti‐human CD34 antibodies stain the blood vessels and lymphatics. However, anti‐ human D2‐40 antibodies stain lymphatics specifically. Capillary invasion is more commonly observed than lymphatic invasion in patients with TNBC. This finding supports the fact that why there was no observed association between a delay in surgery and nodal positivity in the ER‐negative Her2 negative subgroups in the current study.