Breast cancer and thyroid tumore can be regarded as one of the most common cancers in femlaes, and their incidence might be still on the rise, seriously affecting female's healthy life [30–31]. Previous studies have confirmed that thyroid cancer, as the second primary malignant tumor of breast cancer patients (and vice versa), has a high incidence [4, 32]. Multiple studies have shown an association between breast cancer and thyroid cancer. Whereas, the mechanisms involved remained elusive, which can lead to the search for more effective diagnosis and treatment options. At present, pathological assessment and AJCC TNM staging might be still the main diagnostic and prognostic methods for patients with thyroid and breast cancer, but they may not be accurate and sensitive enough for individualized diagnosis and treatment. The patients with the same carcinoma pathological stage may often have different therapeutic effects and clinical outcomes. Furthermore, accurately predicting the prognosis of cancer patients can accelerate the clinician's ability to determine individual treatment strategies by identifying patients' risk status. Therefore, finding new molecular biomarkers to improve patients' prognosis and quality of life can be an urgent task.
Recently, Tsvetkov et al. announced a new form of copper-induced cell death that has become the focus of the scientific community, called cuproposis[16]. It was characterized by the accumulation of intracellular free copper and protein lipidation, triggering cytotoxic stress, which induced cell death. As a program of tumor immunotherapy, cell death attracted increasing attention, including ferroptosis [17], autophagy, apoptosis, necrosis apoptosis [18], as well as cuproptosis induced by ionic carriers acting on copper supplementation. Besides, copper depletion can reduce the activity of angiogenic factors to inhibit vascular development, and copper chelation can be recommended for cancer therapy due to its role as an anti-angiogenic factor [33]. Studies have also shown that copper metabolism is a key factor promoting breast cancer [34–35]. So a treatment aimed at Cuproposis could be a potential strategy for treating cancer. Nevertheless, the value of cuproptosis in cancer prognosis, especially in breast cancer and thyroid cancer, remained unclear. MicroRNA (miRNA) was a class of short non-coding Rnas with about 19 to 25 nucleotides. By binding with complementary targeted mRNAs, the mRNA can be inhibited or degraded, thus affecting cell cycle, metastasis, metabolism and cell death, which were essential regulatory factors in tumor development. Dysregulation of miRNA was often found in the development of malignant tumors, and it can be applied as a potential biomarker for a variety of cancers [36], especially in the exploration of TC and BC therapy, to construct the prognosis characteristics of miRNA targeting CRG.
In this work, we systematically studied the expression of 19 CRGs targeting miRNAs in THCA and BRCA tumor tissues, and the results showed that 35 miRNAs had prognostic value in female patients with THCA and BRCA. We then constructed prognostic features of 15 CrG-targeting miRNAs and demonstrated that these features were independent predictors by multivariate Cox regression analysis. Based on this characteristic, a risk score for each patient was determined. The sample was divided into high-risk and low-risk groups based on the median risk score.The ROC curves and PCA were used to assess the predictive power of constructing this feature. In addition, risk scores and other clinicopathological features were analyzed by univariate and multivariate analyses. The results indicated that risk score can be used as an independent prognostic indicator for THCA and BRCA females. By combining the risk score with these clinicopathological features (age, stage, T stage, N stage, M stage), a novel histogram was constructed to provide personalized predictions.Happily, the charts accurately predicted one -, three - and five-year survival rates for females with thyroid and breast carcinoma. In addition, ssGSEA scores were performed based on THCA and BRCA data sets, so as to estimate the degree of immune infiltration of each sample, and to analyze the correlation and difference of immune infiltration.previous studies have revealed that the immune score is a biomarker to estimate the overall survival rate of TC and BC [37–38]. The patients with a high immune score performed better in chemotherapy and immunotherapy. Based on the significant correlation between the immune score and the risk score, 118 DEGs were obtained by univariate Cox regression analysis compared the immune group and the risk group. Finally, correlation analysis was conducted by combining DEGs and immune infiltration, and six differential expression genes, PCOLCE, SV2C, FBXO45, TSPY4, LIPH and CBLN3, were screened out. The results showed that they were closely related to one or more immune cells and their functions during immune infiltration, which may play a key role in the treatment progress of TC and BC.
Among the prognostic features constructed in this study, most miRNAs have appeared in cancer-related studies. For instance, miR-30e acts as an inhibitor of bone metastasis in breast tumor. In addition, overexpression of miR-30 family restores bone homeostasis by reversing the effects of tumor cell conditioning medium on osteoclast and osteoblast generation [39].miR-346 knockdown inhibited cell growth in colorectal cancer cells by upregulating LHX6 [40]. miR-466 declined the growth and metastasis of prostate cancer by directly targeting the bone-associated transcription factor RUNX2 [41]. miR-765 regulated the growth and metastasis of breast cancer by regulating the Mir-765-ING4 negative feedback loop [42]. These literature studies suggested that miRNA markers associated with cuproptosis may be associated with the progression of TC and BC, and reveal expected targets for the treatment of TC and BC.
Currently, our study may have some limitations, including insufficient sample size and lack of experimental validation. On the one hand, our study relied on publicly available TCGA information, and this miRNA prognostic model associated with cuproptosis needed to be further validated with multi-center, prospective, real-world data. On the other hand, although our study preliminarily identified an association between cuproptosis related miRNAs and anti-tumor immunity, the underlying mechanisms must be further explored through other experiments.