Analyzing the clinical-pathological characteristics of HER-2 ultra-low breast cancer in a medium-sized Brazilian city: a brief communication

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age and tumors showing positivity for estrogen, positivity for progesterone receptors and high levels of the KI-67.
Ductal carcinoma was the predominant subtype.Which is in agreement with the current global epidemiology of breast cancer proposed by World Health Organization (WHO). 11 recent years, there has been a growing number of studies addressing the clinicopathological characteristics of HER-2 low.On the other hand, there are not many studies that address the same characteristics of the ultra-low.Only three studies were found in the world literature describing some clinicopathological characteristics of HER-2 ultra-low breast cancer. 4,7,8luhong et al 7  Regarding immunohistochemical receptors, the estrogen receptor was positive in most of the sample (182, 73,1%).The progesterone receptor was also positive in most cases (162, 67,4%). 4en et al 8 , described 395 patients diagnosed with HER-2 ultra-low breast cancer from January 2018 to December 2019 in an affiliated hospital of a Chinese university.Median age was 51 years old and media between 52-53.Ductal carcinoma represents 331 patients (83,8%).Hormone receptors were positives in 83% of cases.Media of Ki-67 was 15,6. 8nsidering the previously described studies, there was a mild variation about age.In all populations, most of the tumors were positive to ER an PR.In relation to cellular proliferative index (Ki-67), in agreement of the present data, most of cases presented high Ki-67.Chien et.al., were the only who described histologic subtypes of breast cancer HER-2 ultra-low. 8Ductal carcinoma was the most prevalent histologic subtype in their study, as well as in our data.It is in agreement of the well-known epidemiology of breast cancer.
The data from this study have some limitations.
It was carried out in only one institution and the sample used was small.However, there are only three studies describing the clinicopathological characteristics of HER-2 ultra-low tumors.Thus, there is worldwide limitation (not only in Brazil) about HER-2 ultra-low breast cancer cases.In this way, our data can help to consolidate such information in Brazil and in the world, in addition to Immunhistochemistry Autostainer Plus manufacturer's protocols.There were positive and negative internal and external controls.These protocols are according to the recommendations of American Society of Clinical Oncology/College of American Pathologists. 9Sections were analyzed by two pathologists who defined the level of positivity of the markers based on the most current review that discusses the various cut-off points.

RESULTS
A total of 52 samples from women diagnosed with Her-2 ultra-low breast cancer were analyzed.The sample is practically divided in half between biopsies and excisions.Age ranged from 34 to 93 years old (mean: 60 years; SD: 16,28).
The majority of the sample was positive for estrogen and progesterone receptors (88,4 and 78,8% respectively).
Only 11 samples were below the cut-off for the KI-67 marker (SD: 21,1).In terms of histological subtype, ductal carcinoma was the most prevalent.Further data on clinical-pathological characteristics of Her-2 ultra-low breast cancer can be found in Table 1.

FOUNDING SOURCE
There was no founding.

CONFLICT OF INTEREST
Nothing to declare.
, evaluated 85 cases of HER-2 ultra-low in patients diagnosed with breast cancer and undergoing surgery from 2008 to 2019 in a Chinese hospital.Regarding age, 57 patients were over 50 years old (67% of the sample).Hormone receptors were positive in 63 patients (40 of the over 50 years old) and negative in 22.The individual estrogen and progesterone receptor positivity is not reported in the study.The cutoff used in this study for Ki-67 analysis was 14%.Most patients were above the cutoff (55 patients). 7Shi et al 4 , evaluated 1024 patients diagnosed with HER-2 ultra-low breast cancer during the entire period of 2018 at a Chinese university hospital.Most patients were under 55 years old at the time of diagnosis, representing approximately 58,2% of all patients.
10 Cases were subjected to approximate molecular classification following the WHO classification.4Statistics Analysis was carried out using Microsoft Office Excel version 2016.Absolute and relative frequencies (%) and standard deviations (SD) of the results were calculated.The Research Ethics Committee of our institution approved the study with acceptance number CAAE: 36593120.0.0000.5379and approval number 4365915.Written informed consent was waived due to use of anonymized existing medical material or data and the retrospective study design.

Table 1 :
10.34019/1982-8047.2023.v49.42185Bagio et al.Clinicopathologic characteristics HER-2 ultra-low.Distribution of immunohistochemical markers and histologic subtype.The results of this study showed the clinical and pathological profile of HER-2 ultra-low breast cancer in our population is similar to what was described by the WHO: positivity for estrogen and progesterone receptors, high levels of Ki-67 and predominance of ductal carcinomas.More studies are needed to provide the real epidemiology of of HER-2 ultra-low breast cancer in the Brazilian society.It is important to highlight this is the first study in our nation with this aim. CONCLUSION