White light computer-aided optical diagnosis of diminutive colorectal polyps in routine clinical practice.

Background and study aims Artificial Intelligence (AI) systems could make the optical diagnosis (OD) of diminutive colorectal polyps (DCPs) more reliable and objective. This study was aimed at prospectively evaluating feasibility and diagnostic performance of AI-standalone and AI-assisted OD of DCPs in a real-life setting by using a white light-based system (GI Genius, Medtronic Co, Minneapolis, Minnesota, United States). Patients and methods Consecutive colonoscopy outpatients with at least one DCP were evaluated by 11 endoscopists (5 experts and 6 non-experts in OD). DCPs were classified in real time by AI (AI-standalone OD) and by the endoscopist with the assistance of AI (AI-assisted OD), with histopathology as the reference standard. Results Of the 480 DCPs, AI provided the outcome "adenoma" or "non-adenoma" in 81.4% (95% confidence interval [CI]: 77.5-84.6). Sensitivity, specificity, positive and negative predictive value, and accuracy of AI-standalone OD were 97.0% (95% CI 94.0-98.6), 38.1% (95% CI 28.9-48.1), 80.1% (95% CI 75.2-84.2), 83.3% (95% CI 69.2-92.0), and 80.5% (95% CI 68.7-82.8%), respectively. Compared with AI-standalone, the specificity of AI-assisted OD was significantly higher (58.9%, 95% CI 49.7-67.5) and a trend toward an increase was observed for other diagnostic performance measures. Overall accuracy and negative predictive value of AI-assisted OD for experts and non-experts were 85.8% (95% CI 80.0-90.4) vs. 80.1% (95% CI 73.6-85.6) and 89.1% (95% CI 75.6-95.9) vs. 80.0% (95% CI 63.9-90.4), respectively. Conclusions Standalone AI is able to provide an OD of adenoma/non-adenoma in more than 80% of DCPs, with a high sensitivity but low specificity. The human-machine interaction improved diagnostic performance, especially when experts were involved.

Contrast-enhanced ultrasound (CEUS): one step forward in the identification of "high risk" solitary fibrotic tumors of the liver.

BACKGROUND: Solitary fibrous tumors of the liver (SFTL) are rare neoplasms, whose identification and definition of malignant potential are challenging. CASE PRESENTATION: A 62-year-old patient underwent conventional imaging and CEUS to characterize an indeterminate liver lesion after other imaging techniques were inconclusive. In fact, all diagnostic techniques concluded that it was a partially fibrotic lesion, while CEUS determined its extra-hepatocellular origin and malignant potential, initially hypothesized to be a cholangiocarcinoma. Due to the possible risk of seeding following a biopsy procedure, the patient was a candidate for surgery. Subsequently, histopathological examination revealed SFTL. CONCLUSION: CEUS confidently characterized the malignancy and hypothesized the origin of the liver lesion, thus aiding in treatment planning.

The Day-To-Day Practice of MMR and MSI Assessment in Colorectal Adenocarcinoma: What We Know and What We Still Need to Explore.

BACKGROUND: The DNA mismatch repair (MMR) system is a highly preserved protein complex recognizing short insertions, short deletions, and single base mismatches during DNA replication and recombination. MMR protein status is identified using immunohistochemistry. Deficit in one or more MMR proteins, configuring deficient MMR status (dMMR), leads to frameshift mutations particularly clustered in microsatellite repeats. Thus, microsatellite instability (MSI) is the epiphenomenon of dMMR. In colorectal cancer (CRC), MMR/MSI status is a biomarker with prognostic and predictive value of resistance to 5-fluorouracil and response to immune checkpoint inhibitor therapy. SUMMARY: In this Review, we describe the challenges the practicing pathologist may face in relation to the assessment of MMR/MSI status and any open issues which still need to be addressed, focusing on pre-analytic issues, pitfalls in the interpretation, and technical aspects of the different assays. KEY MESSAGES: The current methods of detecting dMMR/MSI status have been optimized for CRCs, and whether these techniques can be applied to all tumor and specimen types is still not fully understood. Following the Food and Drug Administration (FDA), tissue/site agnostic drug approval of pembrolizumab for advanced/metastatic MSI tumors, MMR/MSI status in gastrointestinal tract is a common request from the oncologist. In this setting, several issues still need to be addressed, including criteria for sample adequacy.

Artificial intelligence-assisted optical diagnosis for the resect-and-discard strategy in clinical practice: the Artificial intelligence BLI Characterization (ABC) study.

BACKGROUND: Optical diagnosis of colonic polyps is poorly reproducible outside of high volume referral centers. The present study aimed to assess whether real-time artificial intelligence (AI)-assisted optical diagnosis is accurate enough to implement the leave-in-situ strategy for diminutive (≤ 5 mm) rectosigmoid polyps (DRSPs). METHODS: Consecutive colonoscopy outpatients with ≥ 1 DRSP were included. DRSPs were categorized as adenomas or nonadenomas by the endoscopists, who had differing expertise in optical diagnosis, with the assistance of a real-time AI system (CAD-EYE). The primary end point was ≥ 90 % negative predictive value (NPV) for adenomatous histology in high confidence AI-assisted optical diagnosis of DRSPs (Preservation and Incorporation of Valuable endoscopic Innovations [PIVI-1] threshold), with histopathology as the reference standard. The agreement between optical- and histology-based post-polypectomy surveillance intervals (≥ 90 %; PIVI-2 threshold) was also calculated according to European Society of Gastrointestinal Endoscopy (ESGE) and United States Multi-Society Task Force (USMSTF) guidelines. RESULTS: Overall 596 DRSPs were retrieved for histology in 389 patients; an AI-assisted high confidence optical diagnosis was made in 92.3 %. The NPV of AI-assisted optical diagnosis for DRSPs (PIVI-1) was 91.0 % (95 %CI 87.1 %-93.9 %). The PIVI-2 threshold was met with 97.4 % (95 %CI 95.7 %-98.9 %) and 92.6 % (95 %CI 90.0 %-95.2 %) of patients according to ESGE and USMSTF, respectively. AI-assisted optical diagnosis accuracy was significantly lower for nonexperts (82.3 %, 95 %CI 76.4 %-87.3 %) than for experts (91.9 %, 95 %CI 88.5 %-94.5 %); however, nonexperts quickly approached the performance levels of experts over time. CONCLUSION: AI-assisted optical diagnosis matches the required PIVI thresholds. This does not however offset the need for endoscopists' high level confidence and expertise. The AI system seems to be useful, especially for nonexperts.

Unexpected frequency of genomic alterations in histologically normal colonic tissue from colon cancer patients.

As shown by genomic studies, colorectal cancer (CRC) is a highly heterogeneous disease, where copy number alterations (CNAs) may greatly vary among different patients. To explore whether CNAs may be present also in histologically normal tissues from patients affected by CRC, we performed CGH + SNP Microarray on 15 paired tumoral and normal samples. Here, we report for the first time the occurrence of CNAs as a common feature of the histologically normal tissue from CRC patients, particularly CNAs affecting different oncogenes and tumor-suppressor genes, including some not previously reported in CRC and others known as being involved in tumor progression. Moreover, from the comparison of normal vs paired tumoral tissue, we were able to identify three groups: samples with an increased number of CNAs in tumoral vs normal tissue, samples with a similar number of CNAs in both tissues, and samples with a decrease of CNAs in tumoral vs normal tissue, which may be likely due to a selection of the cell population within the tumor. In conclusion, our approach allowed us to uncover for the first time an unexpected frequency of genetic alteration in normal tissue, suggesting that tumorigenic genetic lesions are already present in histologically normal colonic tissue and that the use in array comparative genomic hybridization (CGH) studies of normal samples as reference for the paired tumors can lead to misrepresented genomic data, which may be incomplete or limited, especially if used for the research of target molecules for personalized therapy and for the possible correlation with clinical outcome.

The 3'-UTR C>T polymorphism of the oxidized LDL-receptor 1 (OLR1) gene does not associate with coronary artery disease in Italian CAD patients or with the severity of coronary disease.

BACKGROUND AND AIM: Oxidized low-density lipoproteins (OxLDLs) play a critical role in endothelial dysfunction, which is implicated in the pathogenesis of atherosclerosis. Vascular endothelial cells internalize and degrade oxLDL through the endothelial lectin-like oxidized LDL receptor 1 (OLR1). OLR1 is up-regulated in several pathological conditions, including hypertension, hyperlipidemia, diabetes, atherosclerosis and inflammation, and represents therefore a good candidate for coronary artery disease (CAD). Recently, a 3'-UTR (188 C>T) SNP in the OLR1 gene has been reported to be associated with coronary artery stenosis and myocardial infarction. In the present study we investigated whether the OLR1 gene 188 C>T SNP is a genetic risk marker for CAD in Italian patients with angiographically defined coronary atherosclerosis, and assessed its relation with clinical and metabolic abnormalities, including severity of disease (classified as restenosis, single- or multiple coronary vessels disease, and MI). METHODS: The 3'-UTR C>T SNP was detected in real-time PCR in 351 subjects with CAD and in 215 control subjects. RESULTS: The OLR1-T allele frequencies were 48.9% in the CAD subjects and 47.7% in controls, with no significant difference between the two groups. Also, the 3'-UTR C>T SNP did not associate with any of the parameters of severity of disease. Furthermore, none of the other clinical and metabolic parameters were associated with the OLR1 gene SNP. CONCLUSIONS: Our observations suggest that, in our population, the 3'-UTR C>T polymorphism of the OLR1 gene is unlikely to play a role in the pathogenesis of coronary artery disease.

Search for genetic variants in the p66Shc longevity gene by PCR-single strand conformational polymorphism in patients with early-onset cardiovascular disease.

BACKGROUND: Among the possible candidate genes for atherosclerosis experimental data point towards the longevity gene p66Shc. The p66Shc gene determines an increase of intracellular reactive oxygen species (ROS), affecting the rate of oxidative damage to nucleic acids. Knock-out p66Shc-/- mice show reduction of systemic oxidative stress, as well as of plasma LDL oxidation, and reduced atherogenic lesions. Thus, p66Shc may play a pivotal role in controlling oxidative stress and vascular dysfunction in vivo. METHODS: We searched for sequence variations in the p66Shc specific region of the Shc gene and its upstream promoter by PCR-SSCP in a selected group of early onset coronary artery disease (CAD) subjects (n. 78, mean age 48.5 +/- 6 years) and in 93 long-living control subjects (mean age 89 +/- 6 years). RESULTS: The analysis revealed two variant bands. Sequencing of these variants showed two SNPs: -354T>C in the regulatory region of p66Shc locus and 92C>T in the p66 specific region (CH2). Both these variants have never been described before. The first substitution partially modifies the binding consensus sequence of the Sp1 transcription factor, and was detected only in two heterozygous carriers (1 CAD subjects and 1 control subject). The 92C>T substitution in the CH2 region consists in an amino acid substitution at codon 31 (proline to leucine, P31L), and was detected in heterozygous status only in one CAD subject. No subjects homozygous for the two newly described SNPs were found. CONCLUSION: Only two sequence variations in the p66Shc gene were observed in a total of 171 subjects, and only in heterozygotes. Our observations, in accordance to other studies, suggest that important variations in the p66Shc gene may be extremely rare and probably this gene is not involved in the genetic susceptibility to CAD.

The adiponectin gene SNP+276G>T associates with early-onset coronary artery disease and with lower levels of adiponectin in younger coronary artery disease patients (age

Adiponectin, an adipocyte-derived protein, is an essential modulator of insulin sensitivity and several studies suggest an important role of adiponectin in the processes leading to atherosclerosis, thus indicating the adiponectin gene as a potential candidate for coronary artery disease (CAD). In the present study we have studied the association between two single nucleotide polymorphisms (SNPs) (+45T>G and +276 G>T) of the adiponectin gene and CAD, looking also into the possible influence of these SNPs on adiponectin plasma levels. The SNPs were analysed in a first cohort of 595 subjects, 325 with CAD and 270 matched controls. We observed a significant association (p<0.001) between the SNP +276G>T in the adiponectin gene and CAD. In multivariate analysis, carriers of the +276G>T SNP had an odds ratio (OR) for CAD of 4.99 (p<0.0007). A strong interaction between the +276G>T SNP and age was also present (OR, 1.03; p<0.0001). The increase in CAD risk was most evident among individuals with early-onset CAD (age T SNP was analysed in a second cohort of CAD and controls. The difference between CAD and controls in the +276G>T SNP frequencies showed a similar trend as before, although not significant. The combination of the two cohorts (1,046 subjects: 580 CAD and 466 controls) showed a statistically significant association, particularly in CAD subjects with early-onset of disease. In addition, we confirmed that in younger CAD subjects the SNP was a significant determinant of lower levels of adiponectin. In view of these results, it could be speculated that the adiponectin gene variant, or a mutation in linkage with it, determines lower adiponectin gene expression, causing in turn an increased risk to develop insulin resistance, atherosclerosis and cardiovascular disease. The significant association of the adiponectin gene in subjects with early-onset CAD also suggests that that genetic factors for late-onset diseases may exert a greater influence in younger persons, when other risk factors are not as prevalent as in older age groups.

The Gly482Ser missense mutation of the peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1 alpha) gene associates with reduced insulin sensitivity in normal and glucose-intolerant obese subjects.

Among the putative candidate genes for insulin resistance, the peroxisome proliferator-activated receptor gamma coactivator-1alpha (PGC-1alpha) is a transcriptional coactivator of PPARgamma and alpha, regulating a wide range of processes involved in energy production and utilization, such as thermogenesis, liver gluconeogenesis, glucose uptake in muscle. In population studies a Gly482Ser substitution in PGC-1alpha has been reported to be associated with increased risk of type diabetes 2 and insulin resistance. In the present study we have analysed the association between the Gly482Ser missense mutation of the PGC-1alpha gene and insulin sensitivity and glucose tolerance in a population of obese non-diabetic subjects. The Gly482Ser SNPs was detected by PCR-RFLP in a cohort of 358 Caucasian obese subjects (223 with normal glucose tolerance (NGT) and 125 with impaired glucose tolerance (IGT). We observed a significant association (p <0.007) between carriers of the Gly482Ser variant of the PGC-1alpha gene and insulin resistance measured by HOMAIR. Multivariate analysis confirmed that the Gly482Ser SNP was a significant (p < 0.02) determinant of decreased insulin sensitivity, independently from other well-known modulators of insulin action. In conclusion, we have found significant association between the Gly482Ser variant of the PGC-1alpha gene and reduced insulin sensitivity in obese subjects. This association resulted independent from all other known modulators of insulin resistance, and suggests a primary role for the PGC-1alpha gene on the genetic susceptibility to insulin resistance in obesity.

Association of the human adiponectin gene and insulin resistance.

Adiponectin is an adipocyte-secreted protein that modulates insulin sensitivity and whose low circulating concentration is associated with insulin resistance. In the present study, we analysed the association between two single-nucleotide polymorphisms (SNPs) in the adiponectin gene and insulin resistance in 253 nondiabetic subjects. In addition, we investigated whether this association is modulated by body mass index (BMI) levels. The SNPs +45T>G and +276G>T in the human adiponectin gene were detected in real-time PCR with LightCycler. No association was found with the +45T>G SNP. The +276G>T SNP was associated with higher BMI (P<0.01), plasma insulin (P<0.02) and HOMA(IR) (P<0.02). To analyse the possible interaction between BMI and the adiponectin gene on insulin resistance, the study group was divided into two subgroups, according to the BMI below or above the median of 26.2 kg/m(2). In both subgroups, subjects carrying the +276G>T SNP had higher HOMA(IR); however, the difference was highly significant among leaner (P<0.001), but not among heavier individuals, indicating that BMI status and the adiponectin gene interact in modulating insulin resistance. Among individuals with BMI <26.2 kg/m(2), the relative risk of insulin resistance was 9.7 (CI: 1.32-87.7, P<0.035). In a subgroup of 67 subjects, carriers of the +276G>T SNP had significantly (P<0.05) lower mean serum adiponectin levels (25.7 ng/ml) compared to noncarriers (37.0 ng/ml), suggesting a possible influence of the +276G>T SNP on adiponectin levels. In summary, we observed an association between the +276G>T SNP in the adiponectin gene and insulin resistance. In particular, among leaner individuals, the adiponectin gene appears to determine an increased risk to develop insulin resistance.

Human resistin gene, obesity, and type 2 diabetes: mutation analysis and population study.

The hormone resistin has been suggested to link obesity to type 2 diabetes by modulating steps in the insulin-signaling pathway and inducing insulin resistance. Thus, the resistin gene represents a potential candidate for the etiology of insulin resistance and type 2 diabetes. In this study, we analyzed the coding sequence of the three exons of the resistin gene, together with its 5' regulatory region and 3' untranslated region (UTR), by single-strand conformation polymorphism (SSCP) in 58 type 2 diabetic subjects, 59 obese subjects, and 60 normal subjects. Only one sequence variant was detected in the resistin gene. Sequencing of this variant revealed the presence of a single nucleotide substitution (SNP) in the 3'-UTR of exon 3 (G1326A) [corrected]. Because 3'-UTR SNPs have been shown to affect gene expression, we examined the frequency of this SNP in 591 subjects (198 obese subjects, 207 diabetic subjects, and 186 control subjects) by PCR amplification and BseRI digestion. No significant association was found between the G1326A [corrected] variant and diabetes and obesity. Comparison of clinical and metabolic parameters between G1326A [corrected] carriers and noncarriers again showed no significant difference. In conclusion, our data suggest that genetic defects of the resistin gene are unlikely to play a role in the etiology of these common disorders in our population.