Interpretation
Although there was a statistical difference in cytoplasmic details
between H-E and Papanicolaou stain in endometrial cells, the grade of
cytoplasmic details was unsatisfied, as well as nuclear details. The
methods might cause the breakdown of DNA and RNA and affect the nucleic
acid structure in the cell nucleus (39). Some studies suggested that H-E
and Papanicolaou stain led to a decrease in DNA recovery, with a degree
of DNA breakage compared to unstained samples (39, 40). The
pre-analytical variables that affect DNA of cytological samples include
specimen collection and processing, properties of cells, cytological
substrate type, fixative, and extraction method (41). Hematoxylin is
used in both methods, which is a Polymerase Chain Reaction inhibitor. It
can stain the nucleus and induce mRNA fragmentation (39). Therefore, it
remains to be investigated whether reducing the dosage of Hematoxylin
can improve the grade of nuclear details and thus affect the
morphological characterization of endometrial cells.
Some patients in the study showed negative histologic results but
malignant cells in cytology (false positive). It is considered to be
related to patient’s thin endometrium which is difficult to be scraped.
In clinic, as for women with postmenopausal vaginal bleeding and thin
endometrial suggested by ultrasound, tissue sampling is more difficult
due to atrophy of cervix and uterine as well as adhesion of cervical
canal. The amount of endometrium that can be extracted is less, and the
failure rate of histological diagnosis is high. Therefore it is easy to
be misdiagnosed (42). Detecting endometrial cells by Li Brush is a
better supplement to histological results (43). However, some patients
showed atypical hyperplasia or endometrial cancer in histology but
negative results in cytology (false negative). The reasons probably
include the following: (1) bias caused by staining method itself; (2)
bias caused by wrong operation process; (3) insufficient sampling of
endometrial cells (42). In practice, process and operation should be
strictly standardized to reduce the occurrence of bias.
In the following study, endometrial cancer will be subdivided into
different pathological patterns through a large sample multi-center
study. The different combination of endometrium will be analyzed and
compared respectively. The improved measures were in order to further
demonstrate that H-E stain might be better than Papanicolaou stain in
endometrial cytology.