Scoring mechanisms of p16INK4a immunohistochemistry based on either independent nucleic stain or mixed cytoplasmic with nucleic expression can significantly signal to distinguish between endocervical and endometrial adenocarcinomas in a tissue microarray study.
BACKGROUND
Endocervical adenocarcinomas (ECAs) and endometrial adenocarcinomas (EMAs) are malignancies that affect uterus; however, their biological behaviors are quite different. This distinction has clinical significance, because the appropriate therapy may depend on the site of tumor origin. The purpose of this study is to evaluate 3 different scoring mechanisms of p16INK4a immunohistochemical (IHC) staining in distinguishing between primary ECAs and EMAs.


METHODS
A tissue microarray (TMA) was constructed using formalin-fixed, paraffin-embedded tissue from hysterectomy specimens, including 14 ECAs and 24 EMAs. Tissue array sections were immunostained with a commercially available antibody of p16INK4a. Avidin-biotin complex (ABC) method was used for antigens visualization. The staining intensity and area extent of the IHC reactions was evaluated using the semi-quantitative scoring system. The 3 scoring methods were defined on the bases of the following: (1) independent cytoplasmic staining alone (Method C), (2) independent nucleic staining alone (Method N), and (3) mean of the sum of cytoplasmic score plus nucleic score (Method Mean of C plus N).


RESULTS
Of the 3 scoring mechanisms for p16INK4a expression, Method N and Method Mean of C plus N showed significant (p-values < 0.05), but Method C showed non-significant (p = 0.245) frequency differences between ECAs and EMAs. In addition, Method Mean of C plus N had the highest overall accuracy rate (81.6%) for diagnostic distinction among these 3 scoring methods.


CONCLUSIONS
According to the data characteristics and test effectiveness in this study, Method N and Method Mean of C plus N can significantly signal to distinguish between ECAs and EMAs; while Method C cannot do. Method Mean of C plus N is the most promising and favorable means among the three scoring mechanisms.
Koo
Chiew-Loon
CL
Department of Pathology, Chung Shan Medical University Hospital, Taichung, Taiwan, ROC. clkoo1510@hotmail.com
Kok
Lai-Fong
LF
Lee
Ming-Yung
MY
Wu
Tina S
TS
Cheng
Ya-Wen
YW
Hsu
Jeng-Dong
JD
Ruan
Alexandra
A
Chao
Kuan-Chong
KC
Han
Chih-Ping
CP
D000230:Adenocarcinoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D014408:Biomarkers, Tumor / Q000378:metabolism; D001706:Biopsy; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000235:genetics / Q000378:metabolism*; D003937:Diagnosis, Differential; D016889:Endometrial Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D040081:Protein Array Analysis; D002583:Uterine Cervical Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology
D014408:Biomarkers, Tumor; D019941:Cyclin-Dependent Kinase Inhibitor p16