Introduction: Colorectal carcinoma is the third most common cancer worldwide. The usual immunophenotype of colorectal adenocarcinoma is CDX2 positive, CK20 positive, and CK7 negative. Aberrant expression is reported in a variety of colorectal carcinomas but its relation to morphological variables and survival data is still unclear. Aim: The aim of this study was to investigate the correlation between the aberrant immunostaining of colorectal carcinoma and different clinicopathological characteristics. Materials and methods: Immunohistochemical expression of CK20, CK7, and CDX2 was evaluated in 71 cases of colorectal carcinoma. Statistical analysis was performed to identify correlations between the morphological characteristics and the immunoprofile of colorectal carcinoma. Results: Positive cytoplasmic and/or membranous signal for CK20 was observed in 66.2% of colorectal carcinomas. CK7 positive immunostaining was seen in 7% of the cases. In terms of combined expression of CK20 and CK7, the proportion of immunoprofile CK20+/CK7− was the highest, accounting for 46 out of 71 colorectal carcinomas, followed by CK20−/CK7−, then CK20−/CK7+ and CK20+/CK7+. Concerning CDX2, the majority of colorectal carcinomas (87.3%) showed positive staining. Statistically significant correlation was established between CDX2 expression and histologic grade and depth of tumour invasion. Loss of CK20 positivity was associated with higher histologic grade. No association between CK7 expression and histopathologic features was established. Conclusions: The results support the heterogeneity of colorectal cancer. Over 35% of the cases in this study showed deviations from the expected immunoprofile. This should be taken into consideration when diagnosing colorectal carcinoma in metastatic regions.

Introduction: The essential tools doctors need to diagnose breast cancer tumors at the early stages and with no clinical presentation are screening mammography and ultrasonography. Nonpalpable breast lesions are a current problem nowadays and there are various types of navigation techniques that are utilized in order to achieve cancer cell-free resection margins in the first place. Intraoperative ultrasound has been proven to be a safe and effective way to excise this type of breast tumors. Aim: To study the correlation between the experience we obtained while using intraoperative ultrasound for excision of nonpalpable breast lesions, and the duration of surgery. Materials and methods: Twenty-five women with nonpalpable breast lesions underwent breast-conserving surgery using ultrasound navigation. Nominal and ordinal data were presented using numbers and percentages. Spearman’s rank-order correlation was used to assess the effect of experience gained on the duration of surgery. Results: The tumor distribution was 72% malignant tumors and 28% benign. A 100% identification rate in the effective surgical excisions was reported. In the process of gaining experience using the method, the duration of surgery shortened by 30%. No tumor cells on ink were found in all specimens and there was no need for secondary surgeries. Conclusions: Our results demonstrate a relatively short learning curve, and we believe that breast surgeons should be helped and encouraged to gather adequate expertise to ensure patient safety and gain confidence.

Introduction: Aberrant expression of CK7/CK20/CDX2 is reported in percentage of colorectal carcinomas (CRC). Aim: The objective of this study was to investigate specific morphological and immunohistochemical characteristics of colorectal carcinoma with KRAS mutation status and microsatellite instability. Materials and methods: Seventy-one patients with CRC and examined KRAS mutation status were included in the investigation. Immunohistochemistry was performed using antibodies to CK7, CK20, CDX2, PMS2, and MSH6. An automatic immunostainer (Ventana BenchMark GX) was used following the manufacturer’ instructions. Fisher’s exact test was used for statistical analysis (p value <0.05). Results: Immunohistochemical analysis was performed for CK7, CK20, CDX2, PMS2, and MSH6. Aberrant expression of the typical immunohistochemical profile CK7/CK20/CDX2 was observed in 50% of the cases. The highest sensitivity and specificity were established for CDX2, with 93% of the cases demonstrating positive nuclear expression in the tumor cells. As for the microsatellite status, 20% of the examined colorectal cancers showed loss in expression for one or both of the mismatch repair proteins - PMS2 and MSH6, which was associated with loss of expression for CK20 and CDX2 as well. Downhill correlation was found also between CK20 expression and the presence of mutation in the gene for KRAS. Conclusions: Our results may support the heterogeneity of colorectal carcinoma. Statistically significant correlation was found between the expression of CK20 and CDX2 and microsatellite deficient and KRAS mutant colorectal cancers. This may lead to application of immunohistochemical screening panel for selection of patients with CRC for genetic testing. Further studies on large cohorts correlating different immunohistochemical profiles to molecular subtypes of colorectal carcinoma are needed for better understanding of the pathogenesis and behavior of colorectal carcinoma.

Background: Metastatic melanoma is an extremely aggressive malignancy with limited therapeutic options, despite advances in targeted and immunotherapy. MicroRNAs are key post-transcriptional regulators of gene expression and play a critical role in tumor adaptation, invasion, and metastasis. The aim of our study was to identify dysregulated miRNAs which may serve as novel biomarkers and therapeutic targets. Materials and Methods: The study was conducted on FFPE samples from metastatic melanoma (n = 15), compared to healthy skin tissue (n = 6). BRAF V600E/Ec mutation status was established by Real-Time qPCR. Expression miRNA analysis was performed, using digital counting of 827 miRNAs on the NanoString platform, with data normalization and fold change calculations. Results: Following normalization and quality control metrics, 58 differentially expressed miRNAs were identified in BRAFwt melanoma samples: 6 overexpressed and 52 inderexpressed miRNAs. In BRAFmut melanoma, 37 microRNAs were differentially expressed: 11 overexpressed and 26 underexpressed. Four miRNAs showed elevated expression in both melanoma groups. Among them, miR-146a-5p and miR-4286 demonstrated the highest elevation, especially in BRAFmut tumors. We focused further on their targeted genes. Conclusion: This study demonstrates significant alterations in the miRNA expression profile in metastatic melanoma and highlights the potential of miR-146a-5p and miR-4286 as key regulators of tumor biology.