Figure 1. Location of CRC in the studied group Figure 2. The frequency of mutations in particular codons of the KRAS gene Figure 3. The frequency of mutations in particular codons of the NRAS gene Figure 4. Differences in CRC localization in patients without KRAS, NRAS or BRAF genes mutations (A) and in patients with mutations in the KRAS, NRAS or BRAF genes (B) Figure 5. Differences in CRC localization in female (A) and male (B) patients with KRAS gene mutations
The 90's of the last century abounded in the discovery of immune checkpoints that means molecules present on the surface of immune system cells regulating its activity. The most important immune checkpoints include: PD-1 and its ligand - PD-L1 and PD-L2 molecules. Both ligands inhibit T cell activity through binding to PD-1 receptor on T cells. Today's immunotherapy is aimed at blocking the immune of checkpoints causing activation of T cell function. This is possible due to specific monoclonal antibodies, including nivolumab, pembrolizumab, atezolizumab, durvalumab and avelumab. The blocking of immunological molecules of immune control points, restores the natural anti-tumor activity of cytotoxic lymphocytes, leading to effective destruction of cancer cells. Previous studies have proved that many types of microRNAs participate in the regulation of the expression of PD-1, PD-L1 and PD-L2 molecules, including miR-200, -197, -33a, -34. The microRNA functions can be attributed to participation in the processes of differentiation, proliferation and apoptosis, migration, metabolism regulation and cellular response to stress. MicroRNAs affect the regulation of approximately 2 / 3 of all genes expression, mainly by blocking translation by joining with the protein complex and the 3'UTR end of mRNA. In each of the studies mentioned, the PD-L1 gene expression is closely correlated with the level of selected microRNAs, which has a huge impact on their functioning. Along with the combination of knowledge about microRNAs and the effectiveness of anti-PD-1 and anti-PD-L1 antibodies treatment of tumors may turn out to contribute in increasing the effectiveness of anticancer therapy.
RT-PCR technique has showed a promising value as pre-screening method for detection of mRNA containing abnormal ALK sequences, but its sensitivity and specificity is still discussable. Previously, we determined the incidence of ALK rearrangement in CNS metastases of NSCLC using IHC and FISH methods. We evaluated ALK gene rearrangement using two-step RT-PCR method with EML4-ALK Fusion Gene Detection Kit (Entrogen, USA). The studied group included 145 patients (45 females, 100 males) with CNS metastases of NSCLC and was heterogeneous in terms of histology and smoking status. 21% of CNS metastases of NSCLC (30/145) showed presence of mRNA containing abnormal ALK sequences. FISH and IHC tests confirmed the presence of ALK gene rearrangement and expression of ALK abnormal protein in seven patients with positive result of RT-PCR analysis (4.8% of all patients, 20% of RT-PCR positive patients). RT-PCR method compared to FISH analysis achieved 100% of sensitivity and only 82.7% of specificity. IHC method compared to FISH method indicated 100% of sensitivity and 97.8% of specificity. In comparison to IHC, RT-PCR showed identical sensitivity with high number of false positive results. Utility of RT-PCR technique in screening of ALK abnormalities and in qualification patients for molecularly targeted therapies needs further validation.
Anti‑programmed death‑1 or anti‑programmed death‑ligand 1 (PD‑L1) blockade may be ineffective in some patients with non‑small cell lung cancer (NSCLC) with high percentage of tumor cells with PD‑L1 expression. In addition, immunotherapy may provide great benefits in patients without PD‑L1 expression. The present study assessed PD‑L1 protein expression by immunohistochemistry, copy number variation (CNV) of PD‑L1 and two single nucleotide polymorphisms (SNPs), rs822335 and rs822336, in the promoter of PD‑L1 by quantitative PCR in 673 patients with NSCLC. Overall survival time of patients with NSCLC depending on the assessed predictive factors (PD‑L1 CNV or SNP) and the treatment methods (immunotherapy in first/second line of treatment or chemotherapy) was analyzed. The present study revealed significantly higher PD‑L1 copies number in patients with ≥10% and ≥50% of tumor cells with PD‑L1 expression compared to patients with lower percentage of PD‑L1‑positive tumor cells (P=0.02 and P=0.0002, respectively). There was a significant positive correlation (R=0.2; P=0.01) between number of PD‑L1 copies and percentage of tumor cells with PD‑L1 protein expression. Percentage of tumor cells with PD‑L1 expression was lower in patients with TT genotype of the rs822335 polymorphism compared to those with CC genotype (P=0.03). The present study observed significantly higher risk of death in patients treated with chemotherapy compared to those treated with immunotherapy (P<0.0001; hazard ratio=2.4768; 95% confidence interval, 2.0120‑3.0490). The present study demonstrated a close relationship between PD‑L1 copies number, genotype of rs822335 PD‑L1 polymorphism and PD‑L1 protein expression on tumor cells. However, the impact of CNV and SNPs of PD‑L1 on overall survival of patients with NSCLC requires further investigation.
The standard diagnostics procedure for non-small-cell lung cancer (NSCLC) requires a pathological evaluation of tissue samples obtained by surgery or biopsy, which are considered invasive sampling procedures. Due to this fact, re-sampling of the primary tumor at the moment of progression is limited and depends on the patient's condition, even if it could reveal a mechanism of resistance to applied therapy. Recently, many studies have indicated that liquid biopsy could be provided for the noninvasive management of NSCLC patients who receive molecularly targeted therapies or immunotherapy. The liquid biopsy of neoplastic patients harbors small fragments of circulating-free DNA (cfDNA) and cell-free RNA (cfRNA) secreted to the circulation from normal cells, as well as a subset of tumor-derived circulating tumor cells (CTCs) or circulating tumor DNA (ctDNA). In NSCLC patients, a longitudinal assessment of genetic alterations in "druggable" genes in liquid biopsy might improve the follow-up of treatment efficacy and allow for the detection of an early progression before it is detectable in computed tomography or a clinical image. However, a liquid biopsy may be used to determine a variety of relevant molecular or genetic information for understanding tumor biology and its evolutionary trajectories. Thus, liquid biopsy is currently associated with greater hope for common diagnostic and clinical applications. In this review, we would like to highlight diagnostic challenges in the application of liquid biopsy into the clinical routine and indicate its implications on the metastatic spread of NSCLC or monitoring of personalized treatment regimens.
The main treatment regimen for small cell lung cancer (SCLC) involves platinum-based chemotherapy (cisplatin or carboplatin) and etoposide. Single nucleotide polymorphisms (SNPs) in
