INTRODUCTION:

Breast cancer is the most common cancer in women and is one of the causes of morbidity and mortality in women worldwide^1,2,3. Based on data from the Global Cancer Observatory (Globocan) in 2020, there were 2 million new cases of breast cancer with around 680,000 deaths worldwide⁴.

In Indonesia in 2020 there were around 65,000 new cases, with an estimated number of cases in the last 5 years amounting to 200,000 cases. Based on data from the Ministry of Health's Basic Health Research (Riskesdas) in 2018, the highest incidence of cancer for women is breast cancer, which is 42.1 per100,000 population, followed by cervical cancer at 23.4 per 100,000 population⁵. In East Kalimantan reported 61,682 cases of breast cancer and as many as 1,879 cases came from Samarinda City in 2013⁵. Based on the medical record data of RSUD Abdoel Wahab Sjahranie Samarinda in 2014 there were 214 cases of breast cancer and 450 cases in 2019⁶. This data shows a significant increase in cases in the last 5 years.

Histopathological examination plays a crucial role in current medical practice. It involves the microscopic examination of tissue specimens to identify cellular and structural changes indicative of various diseases, including cancer and inflammatory conditions. Histopathology aids in accurate diagnosis, prognosis, and treatment planning for patients. It also helps in monitoring treatment responses and disease progression. With advancements in technology and molecular techniques, histopathology continues to be the gold standard for diagnosing many diseases and remains an essential tool in guiding patient care and research⁷.

Human Epidermal Growth Factor Receptor (HER-2) is aprotein-tyrosin kinase receptor involved in the proliferation and division of breast cells. If the expression of the HER-2 gene increases, the gene will make multiple copies of the gene itself. Overexpression of HER-2 Histopathology is the gold standard for clinical diagnosis of cancer and is used for identification of therapeutic targets and prognosis has been associated with poor prognostic factors for breast cancer, such as large tumor size, high mitotic rate, poor differentiation, high proliferative activity, positive lymphnodes,and the presence of hematogenous metastases^8,9

Ki-67 is a nuclear protein that is recognized as a marker of the speed of cell proliferation, located on chromosome 10q25 with the gene code MKI-67^10,11. Ki-67 expression was seen in several phases of the cell cycle,namely G1,S, G2, mitosis, anaphase and telophase, then it was not seen in the G0 phase¹². Expression of Ki-67 affects the rate of cell mitosis so that this examination is important to predict recurrence, prognosis and to determine the success of chemoradiotherapy so that the right choice of therapy is chosen so as to prevent primary tumor metastasis to surrounding tissues^13,14. High Ki-67 expression has a poor prognosis, as it correlates with high cancer stage, poor tumor differentiation, presence of lymph node metastases and distant metastases^15,16.

Histopathological grading is the gold standard for clinical cancer diagnosis and is used to identify therapeutic targets and prognosis¹⁷. Histopathological grading provides a picture of the tumor based on the abnormal condition of tumor cells and tumor tissue seen under the microscope, indicating how fast the tumor grows and spreads. If the tumor cells and tissue arrangement closely resemble the morphology of normal cells and tissue, the tumor is considered well-differentiated. If there are many abnormal cells and little or no normal tissue present, the tumor is said to be poorly differentiated. The more poorly differentiated the cells are, the more the tumor tends to grow and spread rapidly¹⁷.

All invasive breast cancers, including invasive NST breast cancer, routinely undergo histopathological grading based on the assessment of glandular differentiation, nuclear pleomorphism, and the number of mitoses. This histopathological grading is done using the modified Nottingham histologic score by Elston and Ellis¹⁸.

Research conducted at Dr. Saiful Anwar Hospital in Malang by Mahlevi (2016) and Nanto et al. (2017) reported that there is no association between Ki-67 expression and the stage of breast carcinoma, and there is no significant correlation between HER-2 expression and the TNM clinical stage in breast cancer patients^19,20. Hutagalung et al.'s study in 2014 revealed a significant connection between Ki-67 overexpression and the histopathological grade of tumors, as well as a correlation between HER-2 overexpression and high histopathological tumor grades²¹. In line with Gulzar et al. research’s in 2018, they stated that there is a correlation between the histopathological grade and the molecular subtype of breast cancer²².

The Abdoel Wahab Sjahranie Hospital Samarinda is the largest health facility in East Borneo that provides immunohistochemical tests, including HER-2 and Ki-67 protein. Research on the relationship between HER-2 and Ki-67 with the histopathological grade in breast cancer has never been done at Abdoel Wahab Sjahranie Hospital Samarinda, so it is necessary to assess the patient's prognosis and estimate the therapy given.

MATERIALS AND METHODS:

Materials:

The secondary datas were obtained from the medical record room and the laboratory records of the Department of Pathology of Anatomi at Abdoel Wahab Sjahranie Hospital Samarinda Easth Borneo.

Methods:

This study used an observational analytic research design with a cross sectional approach. The study was conducted at the laboratory of Anatomical Pathology and the medical record installation of Abdoel Wahab Sjahranie Hospital Samarinda from October-November 2020. The number of samples in this study was 50 samples. Sampling was done by purposive sampling, namely taking samples based on the objectives of the researcher by meeting the inclusion and exclusion criteria. The inclusion criteria in this study were breastcancer patients who underwent HER-2 and Ki-6 immunohistochemical examinations during 2019. The exclusion criteria in this study were male breast cancer patients and patients with cancer in other organs that were not metastatic breast cancer. There search data were analyzed by using the chi square test (p<0.05).

RESULT:

The results of the study as shown in the distribution of characteristics of breast cancer patients at Abdoel Wahab Sjahranie Hospital Samarinda (Table 1). The age of the most patients was found in the age group >40 years as many as 41 patients (82%).These data have similarities with the previous theory that as many as 75% of women develop breast cancer in the age group above 50 years, only 5% of women develop breast cancer in the age group under 40 years^{23,24,25,26,27}.

Table 1. Characteristics of Breast Cancer Patients at RSUD Abdul Wahab Sjahranie Samarinda

Characteristic	n
Age
<40 years	9 (18%)
≥40years	41 (82%)
ExpressionofHER-2
Positive	22 (44%)
Negative	28 (56%)
ExpressionofKi-67
High	31 (62%)
Low	19 (38%)
Histopathological grade
I	5 (10%)
II	22 (44%)
III	23 (46%)

Based on Table 2, the results of the analysis of the relationship between the expression of HER-2 and Ki-67 with the histopathological grade showed p-values of 0.344 and 0.115, respectively (p>0.05). This indicates that there is no significant relationship between the expression of HER-2 and Ki-67 with the histopathological grade.

The immunohistochemistry examination results of HER-2 expression, Ki-67 expression, and the histopathological grade of breast cancer can be seen below:

Figure 1. The expression of HER-2, Ki-67, and the histopathological grade was assessed through immunohistochemistry examination. HER-2 negative (A), positive (B), Ki-67 low (C), high (D), and Histopathological grade I (E), II (F), III (G) (collected from Abdoel Wahab Sjahranie Hospital, Samarinda).

The analysis of the relationship between HER-2 expression and histopathological grade, as well as the expression of Ki-67 and histopathological grade, can be observed in Table 2.

Table 2. Analysis of the relationship between HER-2 and Ki-67 expressions with the histopathological grade in breast cancer at Abdoel Wahab Sjahranie Hospital Samarinda

Histopathological grade

n(%)

III

n(%)

Total

n(%)

Expression of HER-2

Positive

2(4)

11(22)

9 (18)

22(44)

0.344

0.115

Negative

Expression of Ki-67

High

3(6)

1 (2)

11(22)

14(28)

16(32)

28(56)

31(62)

Low

4(8)

8(16)

7(14)

19(38)

Figure 2. HER-2 (a) and Ki-67 (b) Expression with Histopathological Grade of Breast Cancer at Abdoel Wahab Sjahranie Hospital Samarinda

DISCUSSION:

In the study, the age of the most patients was found in the age group >40 years as many as 41 patients (82%). This can happen because at that age women will experience changes in the menstrual cycle that make them not ovulate, or continue to ovulate but do not produce sufficient progesterone hormone so that the level of the hormone estrogen will increase which stimulates breast cancer²⁸.

Expression of HER-2 was divided into positive and negative, the result found that negative HER-2 expression was the largest group with 28 samples (56%). Increased HER-2 expression is known to be responsible for uncontrolled cell proliferation in breast cancer. Mean while, the mitotic index indicates the aggressiveness of breast cancer and is one of the assessments in the Nottingham grading system. In this study, no significant relationship was found between the histopathological grade and HER-2 expression, which could be due to the uneven distribution of the sample. Higher histopathological grades are recognized as a risk factor for HER-2 gene amplification. In this study, there were fewer cases of histopathological grade II, which might result in less frequent HER-2 amplification compared to grade III, affecting the study's outcomes.

Ki-67 expression was divided into high and low, the results showed that the highest expression (over-expression) of Ki-67 was 31samples (62%). Ki-67 is a proliferation marker, and its expression indicates a relationship with the growth fraction and categorizes patients into good and poor prognosis. Ki-67 overexpression shortens disease-free survival and overall survival, so increased Ki-67 expression is associated with a poor prognosis in breast cancer. Differences in Ki-67 expression results from various researchers may be attributed to a heterogeneous population group, variations in Ki-67 staining, and different Ki-67 expression cutoff points used.

The histopathological grade distribution was classified into three groups: grade I, II, and III. In this study, grade III was the most frequently, with as many as 24 samples (46%), and grade I was obtained by at least 5 patients (10%). The histopathological grade is a tumor picture based on the abnormal condition of tumor cells and tumor tissue seen under a microscope and it is an indicator of the tumor's growth and spread rate. If the tumor cells and tissue composition appear close to the morphology of normal cells and tissues, the tumor is said to be well differentiated. If there are many abnormal cells and little or no normal tissue remains, the tumor is said to be poorly differentiated. The worse the differentiation of cells, the faster tumor will develop and spread²⁹. The results of this study obtained samples with the most grade III, which indicates a lot of abnormal cells so that the tumoris called poorly differentiated.

While research by Gulzar, et al. in 2018 stated that there is a correlation between the histopathological grade and molecular subtypes of breast cancer, where each subtype has a different HER-2 expression²². Hutagalung et al. study in 2014 showed that there was asignificant relationship between Ki-67 overexpression and tumor histopathological grade and there was a significant relationship between HER-2 overexpression and high tumor histopathological grade²¹.

In this study, there was no significant relationship between HER-2 expression and the histopathological grade, which was consistent with the findings of Nanto et al. (2017) which stated that there was no significant relationship between HER-2 expression and the clinical stage of TNM in breast cancer patients²⁰.

Increased HER-2 expression is known to be responsible for uncontrolled cell proliferation in breast cancer. Conversely, the mitotic index serves as an indicator of breast cancer aggressiveness and is one of the components assessed in the Nottingham grading system.

This study did not discover a significant correlation between histopathological grade and HER-2 expression, possibly due to an uneven distribution of research samples. As discussed previously, higher histopathological grades are acknowledged as a risk factor for HER-2 gene amplification. In this research, there were fewer cases of positive HER-2 expression compared to negative HER-2 expression, which might have influenced the study's results.

The number of HER-2 positive samples in the total study sample (Figure 2a) may be consistent due to either the even distribution of the samples or other factors. It can be observed that the number of samples with positive HER-2 expression showed a nearly uniform distribution across all histopathological grades, as did the HER-2 negative samples. While no significant relationship was found between the expression of Ki-67 and the histopathological grade, except for differences in sample distribution, as shown in Table 1 and Figure 2b, high Ki-67 expression appeared equally common in histopathological grades 2 and 3. The observed relationship in this study may be related to the interpretation method employed.

In this study, the interpretation method used for Ki-67 expression is manual, with a reference point set at >15% for high expression (over-expression) and <15% for low expression (low-expression). Most studies use image analysis, which is known to be more accurate³⁰ Another potential reason for the results of this study is the random sampling across all types of breast cancer, as opposed to focusing on a specific breast cancer subtype, as has been the focus in many previous studies.

CONCLUSION:

There is no relationship between HER-2/Ki-67 expression with the histopathological grade of breast cancer in Abdoel Wahab Sjahranie Hospital, Samarinda, East Borneo, Indonesia.

CONFLICT OF INTEREST:

The authors have no conflicts of interest regarding this investigation.

ACKNOWLEGMENT:

Thank’s to the Faculty of Medicine, Mulawarman University of Indonesia, for providing funding for this research.

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Received on 11.09.2023 Revised on 14.10.2024

Accepted on 15.05.2025 Published on 01.10.2025

Available online from October 04, 2025

Research J. Pharmacy and Technology. 2025;18(10):4815-4820.

DOI: 10.52711/0974-360X.2025.00694

This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Creative Commons License.

Expression of Human Epidermal Receptor 2 (HER-2) and Ki-67 is not associated with the histopathological grade in breast cancer at Abdoel Wahab Sjahranie Hospital, Samarinda, East Borneo, Indonesia

RESULT:

CONCLUSION:

ACKNOWLEGMENT: