Breast cancer is the second most prevalent non-skin cancer type (after lung cancer) and the fifth most common cause of cancer death in women, accounting for 10.4% of all cancer incidences [1]. Around one-third of all cancer cases reported in Iraq in 2019 were breast cancer, making it the leading cause of death for Iraqi women [2]. According to the most recent Iraqi Cancer Registry, breast cancer is the most prevalent form of cancer among women in the country, making up around one-third of all female cancer cases that have been documented. This demonstrates that, among the Iranian population as a whole, breast cancer outnumbers even bronchogenic cancer in terms of incidence. The World Health Organization states that the best immediate chance for a decrease in breast cancer mortality is early detection and screening, particularly when paired with appropriate medication. This served as the foundation for the 2001 launch of the Iraqi national program for breast cancer early detection, which aimed to catch the disease early. Since then, all of the major hospitals in the provinces of Iraq have created clinics and specialist centers for the early diagnosis of breast malignancies. Research conducted on patients from the three northern Iraqi governorates revealed that the mean age of individuals diagnosed with breast cancer was 47.4±11.0 years. 60% of patients with breast cancer are under 50 years old and the majority of these diagnoses are made at advanced clinical stages in Kurdish women living in Sulaymanyia, Iraq. More detailed information on the incidence and clinic-pathological characteristics of breast cancer in the middle zone of Iraq was obtained from patient reports from Baghdad, Ramadi-Falluja, Mosul and the middle Euphrates area. According to Basrah reports, females are most commonly affected by breast cancer. Its incidence is higher in industrialized than in developing nations, in part because of differences in risk exposure and, in part, because of improved detection techniques. Evidence from several sources in Basrah, Iraq, indicates that the number of cases of breast cancer has been rising significantly in recent years [3]. Breast cancer is one of the most common cancers among women worldwide and the leading cause of death among Iraqi women [4]. 

There are five key risk factors for breast cancer: age, family history, estrogen, reproductive factor and lifestyle. Ageing is one of the biggest risk factors for breast cancer because of the close association between the disease's prevalence and increasing age. Nearly 25% of cases of breast cancer are influenced by family history. If a woman's mother or sibling has the illness, she is more likely to get it herself. Reproductive variables include early menarche, delayed menopause, age at first pregnancy and low parity can raise the risk of breast cancer. There is a connection between endogenous and exogenous estrogens and a higher risk of breast cancer. 
In premenopausal women, ovariectomies can reduce the risk of breast cancer because the ovary [5]. Controlling the normal mammalian female reproductive physiology requires progesterone [6], When used in conjunction with estrogen during menopausal hormone therapy or as a form of contraception, some exogenous synthetic progestogens (progestins) increase the risk of breast cancer, one important sex steroid hormone that controls a variety of biological functions is estrogen [7,8].

Mucinous glycoprotein CA15-3 is one of the products of the Mucin1 (MUC1) gene. The identification of CA-15-3 is important for breast cancer diagnosis and screening. Patients with breast cancer who were not treated showed much greater serum levels of CA15-3 [9,11]. 

Despite being the most prevalent physiologically active hormone in women, testosterone (T) is referred to as a "male" hormone. It is abundantly (more than 50%) synthesized at the cellular level from androgen precursor in the adrenal gland, ovaries and cells. Numerous studies have shown that androgens preserve the breasts [12].

Given the significance of hormonal and biochemical fluctuations in breast cancer patients, a study was conducted in Kirkuk, Iraq, to examine these patients' pre- and post-chemotherapy hormonal and biochemical changes.

Design of the Study and Gathering of Samples

The current investigation, a retrospective observational analysis, was conducted on 249 patients with breast cancer with a mean age of 47.07 years from February 25 to July 28, 2024, at the Oncology Center in Kirkuk, Iraq. The patients were monitored at two distinct intervals, predominantly prior to receiving chemotherapy and post-chemotherapy. A questionnaire form was used to collect basic data about the patients, such as age and history of chronic conditions. Each patient had a 5 ml blood sample taken for hormonal and biochemical testing.

Tests for hormones and Biochemistry

Tumor marker CA 15-3 kit (from Roche Diagnostics GmbH, Ref No. 03045838122, Germany), for detection of CA 15-3 tumor marker for breast cancer and CA 27.29 (ELISA Kit, from my Biosource) was also used for detection of CA 27.29 tumor marker. Hormonal markers kits included; Testosterone kit (from Roche Diagnostics GmbH, Ref No. 08946353190, Germany), Estrogen kit (from Roche Diagnostics GmbH, Ref No. 06656021190, Germany were utilized likewise. Vit D3 levels were also detected by utilizing of ichroma^TM Vitamin D Neo kit (Document No: INS-VE_E-EN/ Boitech). S. Creatinine and B. Urea were also estimated for the patients

Analytical Statistics

Utilizing the Statistical Package for Scientific Services (SPSS) version 26, computerized statistical analysis was performed. use the paired sample T-test and probability (P) to compare data (p-value). When the P value was less than 0.05, the results were considered statistically significant (S) and when it was less than 0.01 (highly significant, HS).

There was an upregulation of CA 15-3 mean concentration level (40.36 U/mL) among breast cancer patients, this was also applicable for CA 27.29 mean level (41.40 U/mL), while these tumor markers downregulated post-chemotherapy and the results were highly significant (p<0.01) (Table 1).

In regards to Testosterone, Estrogen and Vit. D3 mean levels, our study showed great significant results before and after taking chemotherapy as shown in Table 2.

The current study displayed down regulation of S. Creatinine mean level (1.34 mg/dl) and B. Urea mean level (23.24 mg/dl) post-chemotherapy for the breast cancer patients (Table 3).

The most frequent cancer in women worldwide and the second largest cause of cancer-related mortality worldwide is breast cancer. Its incidence varies throughout multicultural communities, indicating that different etiological causes have different biological expressions and effects on the course of the disease [13,14].

The current study showed an increasing of CA 15-3 mean concentration level (40.36 U/mL) among breast cancer patients, this was also applicable for CA 27.29 mean level (41.40 U/mL), while these tumor markers downregulated post-chemotherapy, these were in line with a study conducted in Baghdad city, where they found that women with breast cancer revealed an elevation of in CA 15-3 and CA 27.29 levels and there was decreasing of their levels post treatment [15]. Our results were also close to another study done in Baghdad city, where they detected a positive correlation between tumor markers and breast cancer [16]. Furthermore the current study exhibited an agreement with Hameed et al. [17] who detected a significant decreasing in CA 15-3 concentration levels post-chemotherapy among breast cancer patient. 

The current study showed increasing in the mean levels of Testosterone, Estrogen before treatment and increased post-treatment, whereas the opposite detected for the Vit D3 mean levels among the breast-cancer patients and the variations were highly significant, these were near to a study done in Anbar city, Iraq, where they found significant differences among breast cancer patients in regards to Testosterone, Estrogen and vitamin D3 levels pre and post treatment [18].

It was also noted that S. Creatinine and B. Urea mean levels elevated among breast cancer patient but significant decreasing in their levels noted post-chemotherapy and the differences were statistically significant, these were close to a study done in Baghdad city, Iraq, where they noticed significant differences in the levels of CA 15-3, S. Creatinine and B. Urea levels before and after getting doses of chemotherapy [19]. Furthermore our study was in line with a study conducted in India where detected high mean levels of B. Urea in late-stages of breast cancer [20].

• Breast cancer prevalence is high in Kirkuk city

• Older ages are more prone to get the disease

• Chemotherapy significantly decreases CA 15-3 and CA 27.29 levels

• Chemotherapy upregulated Vit D3 levels among breast cancer patients

• Testerone and Estrogen elevated in breast cancer patients

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