Unexpected features of breast cancer subtype.
BACKGROUND
Gene expression profiling of breast cancers identifies distinct molecular subtypes that affect prognosis. The aim of this study was to determine whether features of tumors especially the risks of lymph node (LN) metastases differ among molecular subtypes.


METHODS
Subtypes were classified by immunohistochemical surrogates as luminal A, luminalHer2-, luminalHer2+, TNBC, and HER-2+. Data were obtained from an established, registered database of patients with invasive breast cancer treated at our hospital between July 2012 and October 2014. A total of 929 tumors were classifiable into molecular subtypes.


RESULTS
The distribution of subtypes was luminal A (24.2%), luminalHer2- (27.8%), luminalHer2+ (9.1%), TNBC (21.3%), and HER-2+ (17.5%). Marked differences in age, tumor size, extent of lymph node involvement, and grade were observed among subtypes. On univariate analysis, the LN positivity varied across subtypes with 33.6% in luminal A, 40.3% in luminalHer2-, 37.3% in luminalHer2+, 37.6% in TNBC, and 47.4 % in HER-2+ (p=0.201). There was no significant difference in LN positivity among subtypes. On multivariable analysis, grade and tumor size were independent predictors of LN positivity.


CONCLUSIONS
Predictors of LN metastases include higher grade and larger tumor size. Even though breast cancer subtype is not a statistically significant predictor of LN positivity, this information may still be useful in selecting the appropriate therapy in clinical practice.
Department of Oncology, The First Affiliated Hospital of Wenzhou Medical University, South of Bai-xiang Street, Ou-hai District, 325000, Wenzhou, Zhejiang, People's Republic of China. 1259932365@qq.com.
Ye-huan
YH
Liu
Department of Oncology, The First Affiliated Hospital of Wenzhou Medical University, South of Bai-xiang Street, Ou-hai District, 325000, Wenzhou, Zhejiang, People's Republic of China. woc099@sina.com.
Ou-chen
OC
Wang
Department of Oncology, The First Affiliated Hospital of Wenzhou Medical University, South of Bai-xiang Street, Ou-hai District, 325000, Wenzhou, Zhejiang, People's Republic of China. molinsky2005@126.com.
En-dong
ED
Chen
Department of Oncology, The First Affiliated Hospital of Wenzhou Medical University, South of Bai-xiang Street, Ou-hai District, 325000, Wenzhou, Zhejiang, People's Republic of China. 80277179@qq.com.
Ye-feng
YF
Cai
Department of Oncology, The First Affiliated Hospital of Wenzhou Medical University, South of Bai-xiang Street, Ou-hai District, 325000, Wenzhou, Zhejiang, People's Republic of China. 360122473@qq.com.
Chuan-meng
CM
Pan
Department of Oncology, The First Affiliated Hospital of Wenzhou Medical University, South of Bai-xiang Street, Ou-hai District, 325000, Wenzhou, Zhejiang, People's Republic of China. 254997776@qq.com.
Fan
F
Yang
Department of Oncology, The First Affiliated Hospital of Wenzhou Medical University, South of Bai-xiang Street, Ou-hai District, 325000, Wenzhou, Zhejiang, People's Republic of China. oncologyz@yahoo.cn.
Xiao-hua
XH
Zhang
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis*; D001943:Breast Neoplasms / Q000145:classification* / Q000378:metabolism / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008198:Lymph Nodes / Q000378:metabolism / Q000473:pathology*; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D064726:Triple Negative Breast Neoplasms / Q000378:metabolism / Q000473:pathology
D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone