Table 1.

Differential expression of chondroitin sulfate proteoglycan 4 (CSPG4) protein in breast cancer subtypes^*

CSPG4 expression (grade)†	No. of ER+ tumors/total (%)	No. of HER2+ tumors/total (%)	No. of ER−/PR−/HER2− tumors/total (%)
Negative (−)	20/28 (71.4)	15/18 (83.3)	12/44 (27.3)
Weak (+)	6/28 (21.4)	3/18 (16.7)	10/44 (22.7)
Moderate (++)	2/28 (7.2)	0/18 (0.0)	18/44 (40.9)
Strong (+++)	0/28 (0.0)	0/18 (0.0)	4/44 (9.1)

^*Breast cancer subtypes were based on ER, PR, and HER2 expression in primary tumors. Immunohistochemistry (IHC) staining was performed using CSPG4-specific monoclonal antibody (mAb) D2.8.5-C4B8. The ER⁻/PR⁻/HER2⁻ tumors were the triple-negative breast cancer subtype. ER = estrogen receptor; PR = progesterone receptor.

^†Semiquantitative analysis of IHC staining of the cytoplasmic membrane with the CSPG4-specific mAb D2.8.5-C4B8. The staining was graded as − (negative), when no staining was detected; + (weak), when the staining was weak; ++ (moderate), when the staining was homogeneous; +++ (strong), when the staining was strong and homogeneous. The IHC staining was performed once.