Martin D. Berger

Tumor budding in colorectal cancer revisited: results of a multicenter interobserver study.

Tumor budding in colorectal cancer (CRC) is recognized as a valuable prognostic factor but its translation into daily histopathology practice has been delayed by lack of agreement on the optimal method of assessment. Within the context of the Swiss Association of Gastrointestinal Pathology (SAGIP), we performed a multicenter interobserver study on tumor budding, comparing hematoxylin and eosin (H&E) with pan-cytokeratin staining using a 10 high power field (10HPF) and hotspot (1HPF) method. Two serial sections of 50 TNM stage II-IV surgically treated CRC were stained for H&E and pan-cytokeratin. Tumor buds were scored by independent observers at six participating centers in Switzerland and Austria using the 10HPF and 1HPF method on a digital pathology platform. Pearson correlation (r) and intra-class correlation coefficients (ICC) comparing scores between centers were calculated. Three to four times more tumor buds were detected in pan-cytokeratin compared to H&E slides. Correlation coefficients for tumor budding counts between centers ranged from r = 0.46 to r = 0.91 for H&E and from r = 0.73 to r = 0.95 for pan-cytokeratin slides. Interobserver agreement across all centers was excellent for pan-cytokeratin [10HPF: ICC = 0.83 and 1HPF: ICC = 0.8]. In contrast, assessment of tumor budding on H&E slides reached only moderate agreement [10HPF: ICC = 0.58 and 1HPF: ICC = 0.49]. Based on previous literature and our findings, we recommend (1) pan-cytokeratin staining whenever possible, (2) 10HPF method for resection specimens, and (3) 1HPF method for limited material (preoperative biopsy or pT1). Since tumor budding counts can be used to determine probabilities of relevant outcomes and as such more optimally complement clinical decision making, we advocate the avoidance of cutoff scores.

CD8/CD45RO T-cell infiltration in endoscopic biopsies of colorectal cancer predicts nodal metastasis and survival

Background and aimsReliable prognostic markers based on biopsy specimens of colorectal cancer (CRC) are currently missing. We hypothesize that assessment of T-cell infiltration in biopsies of CRC may predict patient survival and TNM-stage before surgery.MethodsPre-operative biopsies and matched resection specimens from 130 CRC patients treated from 2002-2011 were included in this study. Whole tissue sections of biopsy material and primary tumors were immunostained for pancytokeratin and CD8 or CD45RO. Stromal (s) and intraepithelial (i) T-cell infiltrates were analyzed for prediction of patient survival as well as clinical and pathological TNM-stage of the primary tumor.ResultsCD8 T-cell infiltration in the preoperative biopsy was significantly associated with favorable overall survival (CD8i p = 0.0026; CD8s p = 0.0053) in patients with primary CRC independently of TNM-stage and postoperative therapy (HR [CD8i] = 0.55 (95% CI: 0.36-0.82), p = 0.0038; HR [CD8s] = 0.72 (95% CI: 0.57-0.9), p = 0.0049). High numbers of CD8i in the biopsy predicted earlier pT-stage (p < 0.0001) as well as absence of nodal metastasis (p = 0.0015), tumor deposits (p = 0.0117), lymphatic (p = 0.008) and venous invasion (p = 0.0433) in the primary tumor. Infiltration by CD45ROs cells was independently associated with longer survival (HR = 0.76 (95% CI: 0.61-0.96), p = 0.0231) and predicted absence of venous invasion (p = 0.0025). CD8 counts were positively correlated between biopsies and the primary tumor (r = 0.42; p < 0.0001) and were reproducible between observers (ICC [CD8i] = 0.95, ICC [CD8s] = 0.75). For CD45RO, reproducibility was poor to moderate (ICC [CD45i] = 0.16, ICC [CD45s] = 0.49) and correlation with immune infiltration in the primary tumor was fair and non-significant (r[CD45s] = 0.16; p = 0.2864). For both markers, no significant relationship was observed with radiographic T-stage, N-stage or M-stage, indicating that assessment of T-cells in biopsy material can add additional information to clinical staging in the pre-operative setting.ConclusionsT-cell infiltration in pre-operative biopsy specimens of CRC is an independent favorable prognostic factor and strongly correlates with absence of nodal metastasis in the resection specimen. Quantification of CD8i is highly reproducible and allows superior prediction of clinicopathological features as compared to CD45RO. The assessment of CD8i infiltration in biopsies is recommended for prospective investigation.

VE1 immunohistochemistry predicts BRAF V600E mutation status and clinical outcome in colorectal cancer.

Aim VE1 is a monoclonal antibody detecting mutant BRAFV600E protein by immunohistochemistry. Here we aim to determine the inter-observer agreement and concordance of VE1 with mutational status, investigate heterogeneity in colorectal cancers and metastases and determine the prognostic effect of VE1 in colorectal cancer patients. Methods Concordance of VE1 with mutational status and inter-observer agreement were tested on a pilot cohort of colorectal cancers (n = 34), melanomas (n = 23) and thyroid cancers (n = 8). Two prognostic cohorts were evaluated (n = 259, Cohort 1 and n = 226, Cohort 2) by multiple-punch tissue microarrays. VE1 staining on preoperative biopsies (n = 118 patients) was compared to expression in resections. Primary tumors and metastases from 13 patients were tested for VE1 heterogeneity using a tissue microarray generated from all available blocks (n = 100 blocks). Results Inter-observer agreement was 100% (kappa = 1.0). Concordance between VE1 and V600E mutation was 98.5%. Cohort 1: VE1 positivity (seen in 13.5%) was associated with older age (p = 0.0175) and MLH1 deficiency (p < 0.0001). Cohort 2: VE1 positivity (seen in 12.8%) was associated with female gender (p = 0.0016), right-sided tumor location (p < 0.0001), higher tumor grade (p < 0.0001) and mismatch repair (MMR)-deficiency (p < 0.0001). In survival analysis, MMR status and postoperative therapy were identified as possible confounding factors. Adjusting for these features, VE1 was an unfavorable prognostic factor. Preoperative biopsy staining matched resections in all cases except one. No heterogeneity was found across any primary/metastatic tumor blocks. Conclusion VE1 is highly concordant for V600E and homogeneously expressed suggesting staining can be analysed on resection specimens, preoperative biopsies, metastatic lesions and tissue microarrays.

The safety of monoclonal antibodies for treatment of colorectal cancer

ABSTRACT Introduction: Monoclonal antibodies such as bevacizumab, ramucirumab, cetuximab and panitumumab play an important role in the treatment of metastatic colorectal cancer (mCRC). With the introduction of these drugs considerable improvements in both progression-free survival (PFS) and overall survival (OS) were achieved. However these antibodies are associated with a unique side effect profile. Areas covered: This review provides an overview about drug efficacy of bevacizumab, cetuximab, panitumumab and ramucirumab in the treatment algorithm of mCRC. Additionally, we discuss the most common toxicites of these monoclonal antibodies. Expert opinion: The most common toxicities associated with the VEGF-A directed antibody bevacizumab are hypertension, proteinuria, thromboembolism, bleeding, gastrointestinal perforation and prolonged wound healing. Similarly, the rate of hypertension and proteinuria is increased during treatment with the VEGFR2 antibody ramucirumab. On the other hand the most frequent side effects of EGFR targeted antibodies are skin rash, hypersensitivity reactions and hypomagnesemia. Due to the murine portions of cetuximab the incidence of infusion reactions is more frequent compared to panitumumab which is a pure human monoclonal antibody.

Genetic variants of DNA repair-related genes predict efficacy of TAS-102 in patients with refractory metastatic colorectal cancer.

Background Tri-phosphorylated trifluridine (FTD) incorporation into DNA is TAS-102s main anti-tumor action. We tested whether genetic polymorphisms in homologous recombination (HR) and cell cycle checkpoint pathway for DNA repair is associated with outcomes in refractory metastatic colorectal cancer (mCRC) patients treated with TAS-102. Patients and methods We analyzed genomic DNA extracted from 233 samples of three cohorts: an evaluation cohort of 52 patients receiving TAS-102, a validation cohort of 129 patients receiving TAS-102 and a control cohort of 52 patients receiving regorafenib. Single nucleotide polymorphisms of genes involved in HR (ATM, BRCA1, BRCA2, XRCC3, FANCD2, H2AX, RAD51) and cell cycle checkpoint (ATR, CHEK1, CHEK2, CDKN1A, TP53, CHE1, PIN1, PCNA) were analyzed by PCR-based direct sequencing. Results In univariate analysis for the evaluation cohort, patients with any G allele in ATM rs609429 had longer overall survival (OS) than those with the C/C variant (8.7 vs. 4.4 months, HR 0.37, 95% CI: 0.14-0.99, P = 0.022). Patients carrying any A allele in XRCC3 rs861539 had significantly longer progression-free survival (PFS) (3.8 vs. 2.3 months, HR 0.44, 95% CI: 0.21-0.92, P = 0.024) and OS (15.6 vs. 6.3 months, HR 0.25, 95% CI: 0.08-0.79, P = 0.012) than those with the G/G variant. In multivariable analysis, ATM rs609429 remained significant for OS (P = 0.020). In the validation cohort, patients having ATM rs609429 with any G allele showed longer OS and PFS; the G/A variant in XRCC3 rs861539 showed longer OS, though without statistical significance. Conclusion Genetic variants in the HR pathway may predict clinical outcome in mCRC patients receiving TAS-102.

Cytokeratin-20 and Survivin-Expressing Circulating Tumor Cells Predict Survival in Metastatic Colorectal Cancer Patients by a Combined Immunomagnetic qRT-PCR Approach

Circulating tumor cells (CTC) express epithelial and stem cell–like genes, though current approved detection methods mainly use epithelial markers. We optimized a CTC isolation method that could capture their molecular heterogeneity and predict overall survival (OS) in metastatic colorectal cancer (mCRC) patients receiving various chemotherapy regimens. We combined immunomagnetic enrichment of CD45-negative, EpCAM-positive circulating cancer cells with qRT-PCR amplification of CK20 and survivin expression in 88 mCRC patients and 20 healthy controls. We then evaluated the prognostic value of baseline CTC CK20 and survivin expression in mCRC patients. The presence of elevated CTC CK20 or survivin expression distinguished mCRC patients from controls with sufficient sensitivity (79.6%) and specificity (85%). In univariate analysis, patients with high CTC-CK20 expression (9 vs. 33.2+ months, log-rank P < 0.001) or high CTC-survivin expression (10 vs. 33.2+ months, log-rank P = 0.032) had a significantly worse median OS than those with low expression of either marker. In multivariable analysis, the high CTC-CK20 group had significantly shortened OS (HR, 3.11; adjusted P = 0.01), and there was a trend toward inferior OS in the high CTC-survivin group (HR, 1.76; adjusted P = 0.099). Patients with either high CTC CK20 or survivin expression had inferior OS compared with those with low expression of both markers (HR, 4.39; 95% confidence interval, 1.56–12.35; adjusted P = 0.005). Colorectal cancer CTCs can be reliably isolated using epithelial and stem cell markers. CTC CK20 and survivin expression may effectively predict OS in mCRC patients receiving chemotherapy. Mol Cancer Ther; 14(10); 2401–8. ©2015 AACR.

Variations in genes regulating tumor-associated macrophages (TAMs) to predict outcomes of bevacizumab-based treatment in patients with metastatic colorectal cancer: results from TRIBE and FIRE3 trials

BACKGROUND Tumor-associated macrophages (TAMs) with the M2-like phenotype are regulated by mainly NF-kB pathway including TBK1, which can influence tumor progression by secretion of proangiogenic factors such as vascular endothelial growth factor. The CCL2/CCR2 axis, histidine-rich glycoprotein (HRG), and placenta growth factor (PIGF) play a critical role in the polarization of M1/M2 phenotypes and the recruitment of TAMs to tumor microenvironment. We therefore hypothesized that variations in genes involved in regulating TAMs may predict clinical outcomes of bevacizumab treatment in patients with metastatic colorectal cancer (mCRC). PATIENTS AND METHODS We analyzed genomic DNA extracted from samples of patients receiving bevacizumab plus FOLFIRI as a first-line treatment using PCR-based direct sequencing. Twelve functional single-nucleotide polymorphisms in eight genes (CCL2, CCR2, HRG, PIGF, NFKB1, TBK1, CCL18, and IRF3) were tested for associations with clinical outcomes in a discovery cohort of 228 participants in TRIBE trial (NCT00719797), then validated in 248 KRAS exon2 (KRAS) wild-type participants in FIRE3 trial (NCT00433927). FIRE3-cetuximab cohort served as a negative control. RESULTS TBK1 rs7486100 was significantly associated with overall survival in 95 KRAS wild-type patients of TRIBE cohort in univariate analysis and had a strong trend in multivariable analysis; furthermore, the association of the T allele was observed for progression-free survival (PFS) in both univariate and multivariable analyses in FIRE3-bevacizumab but not cetuximab cohort. CCL2 rs4586, CCL18 rs14304, and IRF3 rs2304205 had univariate and multivariable correlations with PFS in KRAS mutant patients of the TRIBE cohort, whereas they had no correlations in KRAS wild-type patients of the TRIBE cohort. No association was seen in control cohort. CONCLUSIONS Our study demonstrates for the first time that variations in genes regulating TAMs-related functions are significantly associated with clinical outcomes in mCRC patients treated with bevacizumab-containing chemotherapy. These results also suggest that some TAM-related gene variations may predict outcomes of bevacizumab treatment in KRAS status-dependent manner.

Impact of sex, age, and ethnicity/race on the survival of patients with rectal cancer in the United States from 1988 to 2012

Most studies report on colon and rectal cancers collectively, even though biologic and prognostic differences exist between these disease entities. Here, we investigated the effects of sex, age, and ethnicity/race on rectal cancer (RC) mortality by stage focusing on differences before and after 2004. Using the SEER database, we identified 105,511 patients diagnosed with RC from 1988-2012. Main outcomes were disease-specific survival (DSS) and overall survival (OS). In patients with stage I-III RC, women achieved a longer DSS (HR 0.87, P < 0.001) than men, independent of age, from 1988-2012. In stage IV disease, the sex disparity favoring women was limited to the age 18-44 yr cohort (DSS HR 0.79, P < 0.001). The sex difference in DSS (Pinteraction = 0.009) was significantly reduced from 2004 to 2012 across all ages. Hispanics and Native Americans with locoregional RC had inferior DSS relative to Whites from 1988-2003, but these differences were not evident from 2004-2012 (Pinteraction = 0.001). Additionally, Asians with stage I-III RC had superior DSS from 2004 on compared to Whites. Mortality in African American patients improved modestly overall and remained significantly higher than other ethnicities/races across all stages. Sex disparities have narrowed in patients with metastatic RC, but persist in patients with stage I-III disease. These differences are most evident among young patients (18-44 years), where sex disparities have even widened in stage I-III disease. While outcomes have improved for Asians, Hispanics, and Native Americans with stage I-III rectal cancer, black-white disparities remain in all disease stages.

Comprehensive assessment of tumour budding on cytokeratin stains in colorectal cancer.

Tumour budding in colorectal cancer (CRC) is a recognized prognostic parameter. The aim of this study was to address the use of cytokeratin immunostaining for the visualization and scoring of tumour buds.

Colorectal cancer: epigenetic alterations and their clinical implications.

Colorectal cancer (CRC) is a heterogeneous disease with distinct molecular and clinical features, which reflects the wide range of prognostic outcomes and treatment responses observed among CRC patients worldwide. Our understanding of the CRC epigenome has been largely developed over the last decade and it is now believed that among thousands of epigenetic alterations present in each tumor, a small subgroup of these may be considered as a CRC driver event. DNA methylation profiles have been the most widely studied in CRC, which includes a subset of patients with distinct molecular and clinical features now categorized as CpG island methylator phenotype (CIMP). Major advances have been made in our capacity to detect epigenetic alterations, providing us with new potential biomarkers for diagnostic, prognostic and therapeutic purposes. This review aims to summarize our current knowledge about epigenetic alterations occurring in CRC, underlying their potential future clinical implications in terms of diagnosis, prognosis and therapeutic strategies for CRC patients.