Clinical utility of ABCB1 and ABCG2 genotyping for assessing the clinical and pathological response to FAC therapy in Mexican breast cancer patients.

PURPOSE: Resistance to neoadjuvant chemotherapy with 5-fluorouracil, doxorubicin, and cyclophosphamide (FAC) in some patients with locally advanced breast cancer remains one of the main obstacles to first-line treatment. We investigated clinical and pathological responses to FAC neoadjuvant chemotherapy in Mexican women with breast cancer and their possible association with SNPs present in ABC transporters as predictors of chemoresistance. MATERIALS: A total of 102 patients undergoing FAC neoadjuvant chemotherapy were included in the study. SNP analysis was performed by RT-PCR from genomic DNA. Two SNPs were analyzed: ABCB1 rs1045642 (3435 C > T) and ABCG2 rs2231142 (421 G > T). RESULTS: In clinical response evaluation, significant associations were found between the ABCB1 C3435T genotype and breast cancer chemoresistant and chemosensitive patients (p < 0.05). In the early clinical response, patients with genotype C/C or C/T were more likely to be chemosensitive to neoadjuvant therapy than patients with genotype T/T (OR = 4.055; p = 0.0064). Association analysis between the ABCB1 gene polymorphism and the pathologic response to FAC chemotherapy showed that the C/C + C/T genotype was a protective factor against chemoresistance (OR = 3.714; p = 0.0104). Polymorphisms in ABCG2 indicated a lack of association with resistance to chemotherapy (p = 0.2586) evaluating the clinical or pathological response rate to FAC neoadjuvant chemotherapy. CONCLUSION: The early clinical response and its association with SNPs in the ABCB1 transporter are preserved until the pathological response to neoadjuvant chemotherapy; therefore, it could be used as a predictor of chemoresistance in locally advanced breast cancer patients of the Mexican population.

Chemoresistance in Breast Cancer Patients Associated With Changes in P2X7 and A2A Purinergic Receptors in CD8+ T Lymphocytes.

Breast cancer (BRCA) is the most frequent cancer type that afflicts women. Unfortunately, despite all the current therapeutic strategies, many patients develop chemoresistance hampering the efficacy of treatment. Hence, an early indicator of therapy efficacy might aid in the search for better treatment and patient survival. Although emerging evidence indicates a key role of the purinergic receptors P2X7 and A2A in cancer, less is known about their involvement in BRCA chemoresistance. In this sense, as the chemotherapeutic treatment stimulates immune system response, we evaluated the expression and function of P2X7 and A2A receptors in CD8+ T cells before and four months after BRCA patients received neoadjuvant chemotherapy. The results showed an increase in the levels of expression of P2X7 and a decrease in the expression of A2A in CD8+ T cells in non-chemoresistant (N-CHR) patients, compared to chemoresistant (CHR) patients. Interestingly, in CHR patients, reduced expression of P2X7 occurs along with a decrease in the CD62L shedding and the production of IFN-γ. In the case of the A2A function, the inhibition of IFN-γ production was not observed after chemotherapy in CHR patients. A possible relationship between the modulation of the expression and function of the P2X7 and A2A receptors was found, according to the molecular subtypes, where the patients that were triple-negative and human epidermal growth factor receptor 2 (HER2)-enriched presented more alterations. Comorbidities such as overweight/obesity and type 2 diabetes mellitus (T2DM) participate in the abnormalities detected. Our results demonstrate the importance of purinergic signaling in CD8+ T cells during chemoresistance, and it could be considered to implement personalized therapeutic strategies.

Determination of sialic acid in saliva by means of surface-enhanced Raman spectroscopy as a marker in adnexal mass patients: ovarian cancer vs benign cases.

BACKGROUND: To demonstrate the use of surface-enhanced Raman spectroscopy (SERS) to determine sialic acid (SA) levels in saliva using silver nanoparticles as substrates, in adnexal mass patients scheduled for surgical intervention to remove invasive masses, with the aim to compare SA levels in benign tumor vs ovarian cancer patients. METHODS: Quantification of SA levels was accomplished by measuring their SERS and calibrating with analytical reagent SA. The mean SA concentration in saliva from 37 benign adnexal mass resulted smaller (5.1 mg/dL) than the mean concentration in 15 Ovarium cancer patients (23 mg/dL). The cancer condition was determined by biopsy of the removed adnexal mass. The CA-125 biomarker was also measured. The predictive potential of both biomarkers is discussed, together with the malignity risk index (MRI). RESULTS: Our results showed a sensitivity/specificity of 80%/100% with a cutoff to distinguish between benign/cancer cases of SA 15.5 mg/dL, as established from a ROC analysis. Our results suggest that SA may be a more useful biomarker than CA-125 to detect ovarian cancer. CONCLUSIONS: Our results suggest that the SA levels measured from saliva may be as good predictors as the MRI index for the presence of ovarian cancer in sensitivity/negative predictive value and outperforms it in specificity/positive predictive value.