Characteristics and relationships of histological grade and the expression of Ki-67 antigen in different molecular classification of ductal carcinoma in situ

Abstract

Objective To investigate the characteristics and relationships of histological grade and Ki-67 antigen in different molecular classification of ductal carcinoma in situ (DCIS). Methods The expression of estrogen receptor(ER), progesterone receptor(PR), Her-2 and Ki-67 were detected by using immmunohistochemistry in 48 cases of DCIS with complete pathological information.The molecular classification was done in order to analyze the characteristics and relationships of histological grade and Ki-67 in different subtypes. Results Luminal A type, Luminal B type, Her-2 overexpression type and triple negative type were 24 cases, 16 cases, 6 cases and 2 cases in 48 DCIS, respectively.The compositional ratios of Luminal A and triple negative type in DCIS were significantly different from the ones in invasive ductal carcinoma (χ2=12.874, P<0.01; χ2=4.703, P<0.05). The low, middle and high grade were 6 cases, 12 cases and 30 cases in 48 DCIS, respectively.The low and middle grade was only found in Luminal type, and the proportion of high grade in Luminal A was 41.67%, which was obviously lower than those in Luminal B (75.00%) and Her-2 overexpression type (100.00%) (χ2=4.310, P<0.05; χ2=5.563, P<0.05). Significant difference of the compositional ratio of low and middle grade was detected between Luminal and non-Luminal type (χ2=5.760, P<0.05). Obvious differences of Ki-67 index were found in different subtypes (F=24.793, P<0.01). The Ki-67 index and positive rate in Luminal were obviously lower than those in non-Luminal (t=4.213, P<0.01; χ2=8.515, P<0.01). Different histological grade was accompanied with different Ki-67 index in DCIS (F=4.270, P<0.05), and both of which had positive correlation (r=0.367, P<0.05). The Ki-67 index and positive rate in low and middle grade were obviously lower than those in high grade(t=2.876, P<0.01; χ2=4.914, P<0.05). Conclusion Different molecular classification of DCIS has different histological grade and Ki-67 expression, and histological grade is positively correlated with Ki-67 expression, which may be an important indication of DCIS prognosis. Key words: Carcinoma, ductal, breast; Molecular classification; Histological grade; Ki-67 antigen; Correlation