Breast cancer is the most common cancer in women and represents the leading cause of cancer mortality among this gender worldwide. It stands as the most frequent malignancy in females, thus signifying a principal focus of biomedical research [11].
The prevalence and incidence rates of breast cancer are progressively escalating across all global regions. The National Cancer Registry Program's 2013 report in Egypt reveals that breast cancer is the most pervasive form of cancer among females, accounting for 32% of all female cancer cases. [12, 13].
Innovative biomarkers are required for early detection, treatment, and prognosis. Non-coding RNAs (ncRNAs) have emerged as crucial players in various stages of breast cancer tumorigenesis, influencing cell death, metabolism, epithelial-mesenchymal transition (EMT), metastasis, and drug resistance [14].
The current study showed a significant decrease in expression levels of long non-coding RNA (NKILA) in tumour tissue compared to normal tissue (p < 0.001). NKILA expression levels in tissues showed high sensitivity and specificity, so had a significant diagnostic value for breast cancer patients.
In consistent with our results, Studies by Di Huang and colleagues, Li-Hua Luo and colleagues also reported a decrease in NKILA expression in breast cancer tissues and its involvement in inhibiting tumor progression, including cell proliferation, migration, and angiogenesis, indicating its potential as a therapeutic target [15, 16]. Our finding aligns with several other studies in various cancer types, such as non-small cell lung cancer, melanoma, hepatocellular carcinoma (HCC), and rectal cancer, where NKILA expression was also found to be downregulated in tumor tissues [17–20].
The current study observed that altered NKILA expression was associated with specific tumor characteristics in breast cancer, including positive family history, invasive lobular carcinoma, high-grade tumors, negative estrogen and progesterone receptors, and advanced lymph node involvement. These findings suggest that NKILA could serve as an important biomarker in breast cancer diagnosis and prognosis.
Consistent with our results Huang and colleagues found that NKILA levels were decreased in breast cancerous tissue compared to non-cancerous tissues and were correlated with lymph node involvement and higher TNM stage [15]. Moreover, Studies by Luo and Wu reported correlations between NKILA expression and clinical stage, TNM classification, and epithelial-mesenchymal transition (EMT) features [21, 16]. Liu and colleagues found that NKILA expression was independent prognostic factor. Furthermore, low NKILA expression is associated with breast cancer metastasis and poor patient prognosis which confirm our results [22].
NF-KP was significantly increased in in tumor tissue compared to normal tissue (p < 0.001) and a significant negative correlation between NKILA and NF-KB in breast cancer was found. This suggests a regulatory interplay between these molecules, where higher NKILA expression is associated with lower NF-KB expression and vice versa. This inverse correlation may indicate that NKILA has a potential inhibitory role in suppressing NF-KB activity, which plays a critical role in cancer-related processes, thereby affecting breast cancer pathogenesis. In accordance with our findings, Huang et al., have demonstrated that NKILA interacts with the NF-κB–IκBα complex by binding to p65 and modulates T cell activation-induced cell death by inhibiting NF-κB activity [15].
The current study has demonstrated an increase in CXCL-1 expression in breast cancer tissue as compared to normal tissue (p < 0.001). This elevation was particularly prominent in cases characterized by tumour sizes exceeding 5, invasive lobular carcinoma (ILC) type, cases graded as 3, and those with tumour stages classified as T3 or T4. These findings underscore the upregulation of CXCL-1 in breast cancer, specifically in aggressive subtypes.
These findings were in line with Wang et al., who found a correlation between elevated CXCL1 expression and advanced cancer stage, lymph node metastasis, and poor survival. The study's findings brought attention to the value of the CXCL1-NF-κB axis in propelling breast cancer growth and metastasis [23].
This prove that CXCL1 and NF-κB may serve as a potential therapeutic target for the prevention of cancer growth metastasis.
The current study found a highly significant decrease in LINC00993 expression in breast cancer tumour tissues compared to normal tissues (p < 0.001). LINC00993 expression levels in tissues showed high sensitivity and specificity, so had a significant diagnostic value for breast cancer patients.
In accordance with our results [24, 8, 25] reported significant downregulation of LINC00993 in triple-negative breast cancer (TNBC) and its association with luminal breast cancer.
The study by Guo et al. found that higher expression of LINC00993 was associated with a better outcome in TNBC patients, indicating its prognostic value [8].
Our study found that expression of LINC00993 was associated with invasive lobular carcinoma (ILC) type, high-grade tumours (Grade 3), and advanced lymph node involvement (N3). These findings suggest LINC00993 may have a significant role in breast cancer pathogenesis as their expression levels are associated with specific tumour characteristics. Chen et al., has demonstrated discernible patterns of LINC00993 expression across various subtypes of breast cancer, thereby underscoring its potential significance in distinguishing between different types of breast cancer. These findings are consistent with the results of our own study [25].
The current investigation has a positive correlation between the expression levels of NKILA and LINC00993 in cases of breast cancer. This finding suggests a potential for these lncRNAs to regulate the pathogenesis of breast cancer. The observed positive correlation supports the notion that NKILA and LINC00993 may function in concert to influence cancer-related pathways or mechanisms in breast cancer. These lncRNAs hold promise as tumour biomarkers of value and therapeutic targets for personalized breast cancer treatment strategies.