Tumor Regression Grade After Neoadjuvant Chemoradiation and Surgery for Low Rectal Cancer Evaluated by Multiple Correspondence Analysis: Ten Years as Minimum Follow-up

Spatial transcriptomic analysis reveals local effects of intratumoral fusobacterial infection on DNA damage and immune signaling in rectal cancer

Mucinous colorectal cancer (CRC) is a common histological subtype of colorectal adenocarcinoma, associated with a poor response to chemoradiotherapy. The commensal facultative anaerobes fusobacteria, have been associated with poor prognosis specifically in mesenchymal CRC. Interestingly, fusobacterial infection is especially prevalent in mucinous CRC. The objective of this study was therefore to increase our understanding of beneficial and detrimental effects of fusobacterial infection, by contrasting host cell signaling and immune responses in areas of high vs. low infection, using mucinous rectal cancer as a clinically relevant example. We employed spatial transcriptomic profiling of 106 regions of interest from 8 mucinous rectal cancer samples to study gene expression in the epithelial and immune segments across regions of high versus low fusobacterial infection. Fusobacteria high regions were associated with increased oxidative stress, DNA damage, and P53 signaling. Meanwhile regions of low fusobacterial prevalence were characterized by elevated JAK-STAT, Il-17, Il-1, chemokine and TNF signaling. Immune masks within fusobacterial high regions were characterized by elevated proportions of cytotoxic (CD8+) T cells (p = 0.037), natural killer (NK) cells (p < 0.001), B-cells (p < 0.001), and gamma delta T cells (p = 0.003). Meanwhile, fusobacteria low regions were associated with significantly greater M2 macrophage (p < 0.001), fibroblast (p < 0.001), pericyte (p = 0.002), and endothelial (p < 0.001) counts.

An investigation into tumor regression grade as a parameter for locally advanced rectal cancer and 5-year overall survival rate

PURPOSE

The standard treatment for locally advanced rectal cancer (LARC) is neoadjuvant chemoradiation (nCRT) followed by surgery. Several parameters are associated with patient survival in LARC. One of these parameters is tumor regression grade (TRG); however, the significance of TRG remains controversial. In this study, we aimed to examine the correlations of TRG with 5-year overall (OS) and relapse-free survival (RFS) and identify other factors that influence the survival rates in LARC after nCRT followed by surgery.

METHODS

This retrospective study included 104 patients diagnosed with LARC who underwent nCRT followed by surgery at Songklanagarind Hospital from January 2010 to December 2015. All patients received fluoropyrimidine-based chemotherapy at a total dose of 45.0 to 50.4 Gy in 25 daily fractions. Tumor response was evaluated using the 5-tier Mandard TRG classification. TRG was categorized into good (TRG 1-2) and poor (TRG 3-5) responses.

RESULTS

TRG (classified by either the 5-tier classification system or the 2-group classification system) was not correlated with 5-year OS or RFS. The 5-year OS rates were 80.0%, 54.5%, 80.8%, and 67.4% in patients with TRG 1, 2, 3, and 4, respectively (P=0.22). Poorly differentiated rectal cancer and systemic metastasis were associated with poor 5-year OS. Intraoperative tumor perforation, poor differentiation, and perineural invasion were correlated with inferior 5-year RFS.

CONCLUSION

TRG was probably not associated with either 5-year OS or RFS; however, poor differentiation and systemic metastasis were strongly associated with poor 5-year OS.

Use of Multiple Correspondence Analysis and K-means to Explore Associations Between Risk Factors and Likelihood of Colorectal Cancer: Cross-sectional Study

BACKGROUND

Previous works have shown that risk factors are associated with an increased likelihood of colorectal cancer.

OBJECTIVE

The purpose of this study was to detect these associations in the region of Lleida (Catalonia) by using multiple correspondence analysis (MCA) and k-means.

METHODS

This cross-sectional study was made up of 1083 colorectal cancer episodes between 2012 and 2015, extracted from the population-based cancer registry for the province of Lleida (Spain), the Primary Care Centers database, and the Catalan Health Service Register. The data set included risk factors such as smoking and BMI as well as sociodemographic information and tumor details. The relations between the risk factors and patient characteristics were identified using MCA and k-means.

RESULTS

The combination of these techniques helps to detect clusters of patients with similar risk factors. Risk of death is associated with being elderly and obesity or being overweight. Stage III cancer is associated with people aged ≥65 years and rural/semiurban populations, while younger people were associated with stage 0.

CONCLUSIONS

MCA and k-means were significantly useful for detecting associations between risk factors and patient characteristics. These techniques have proven to be effective tools for analyzing the incidence of some factors in colorectal cancer. The outcomes obtained help corroborate suspected trends and stimulate the use of these techniques for finding the association of risk factors with the incidence of other cancers.

The Use of Multiple Correspondence Analysis to Explore Associations Between Categories of Qualitative Variables and Cancer Incidence

BACKGROUND

Previous works have shown that risk factors for some kinds of cancer depend on people's lifestyle (e.g. rural or urban residence). This article looks into this, seeking relationships between cancer, age group, gender and population in the region of Lleida (Catalonia, Spain) using Multiple Correspondence Analysis (MCA).

METHODS

The dataset analysed was made up of 3408 cancer episodes between 2012 and 2014, extracted from the Population-based Cancer Registry (PCR) for Lleida province. The cancers studied were colon and rectal (1059 cases), lung (551 cases), urinary bladder (446 cases), prostate (609 cases) and breast (743 cases). The MCA technique was applied and used to search relationships among the main qualitative features. The basic statistics were the percentage explaining (variance), the inertia and the contribution of each qualitative variable.

RESULTS

General outcomes showed a low and moderate contribution of living in rural areas to colorectal and male prostate cancer. Males in urban areas were slightly and heavily affected by lung and urinary bladder cancer respectively. The analysis of each cancer provided additional information. Colorectal cancer greatly affected males aged <60, urban residents aged 70-79, and rural females aged ≥ 80. The impact of lung cancer was high among urban females <60, moderate among males aged 70-79 and high among rural females aged ≥ 80. The results for urinary bladder cancer results were similar to those for lung cancer. Prostate cancer affected both the <60 and ≥ 80 age groups significantly in rural areas. Breast cancer hit the 70-79 group significantly and, somewhat less so, rural females aged ≥ 80.

CONCLUSIONS

MCA was a significant help for detecting the contributions of qualitative variables and the associations between them. MCA has proven to be an effective technique for analyzing the incidence of cancer. The outcomes obtained help to corroborate suspected trends, as well as detecting and stimulating new hypotheses about the risk factors associated with a specific area and cancer. These findings will be helpful for encouraging new studies and prevention campaigns to highlight observed singularities.

Is Metformin Associated With Improved Response to Neoadjuvant Chemoradiotherapy in Locally Advanced Rectal Cancer?

Efforts to determine whether metformin can increase the effectiveness of neoadjuvant chemoradiotherapy in rectal cancer have increased in recent years. However, retrospective studies have yielded inconclusive results.

OBJECTIVES

The aim of this study was to compare oncological outcomes and survival after neoadjuvant chemoradiotherapy in patients with rectal cancer taking metformin versus in those not taking metformin.

METHODS

This study analyzed 423 consecutive patients with locally advanced rectal cancer who underwent neoadjuvant chemoradiotherapy and curative surgery between January 2010 and May 2020; of these, 59 were taking metformin and 364 were not taking metformin.

RESULTS

Patients taking metformin had a lower proportion of tumor regression (6.8% versus 22.0%, P = 0.012) as well as a lower proportion of patients achieving a pathological complete response (6.8% versus 20.6%, P = 0.011). In the multivariate analysis, independent predictors of pathologic complete response were not taking metformin (OR: 5.26, 95% CI: 1.12-24.85, P= 0.035) and cT2 stage (OR: 3.49, 95% CI: 1.10-11.07, P= 0.034); the interval was also an independent predictor of tumor regression (OR: 1.78, 95% CI: 1.06-2.96, P= 0.028). No differences were observed in survival between groups.

CONCLUSION

Metformin was not associated with better tumor responses or survival after neoadjuvant treatment.

Genomic Analysis of Response to Neoadjuvant Chemotherapy in Esophageal Adenocarcinoma

Neoadjuvant therapy followed by surgery is the standard of care for locally advanced esophageal adenocarcinoma (EAC). Unfortunately, response to neoadjuvant chemotherapy (NAC) is poor (20-37%), as is the overall survival benefit at five years (9%). The EAC genome is complex and heterogeneous between patients, and it is not yet understood whether specific mutational patterns may result in chemotherapy sensitivity or resistance. To identify associations between genomic events and response to NAC in EAC, a comparative genomic analysis was performed in 65 patients with extensive clinical and pathological annotation using whole-genome sequencing (WGS). We defined response using Mandard Tumor Regression Grade (TRG), with responders classified as TRG1-2 (n = 27) and non-responders classified as TRG4-5 (n =38). We report a higher non-synonymous mutation burden in responders (median 2.08/Mb vs. 1.70/Mb, p = 0.036) and elevated copy number variation in non-responders (282 vs. 136/patient, p < 0.001). We identified copy number variants unique to each group in our cohort, with cell cycle (CDKN2A, CCND1), c-Myc (MYC), RTK/PIK3 (KRAS, EGFR) and gastrointestinal differentiation (GATA6) pathway genes being specifically altered in non-responders. Of note, NAV3 mutations were exclusively present in the non-responder group with a frequency of 22%. Thus, lower mutation burden, higher chromosomal instability and specific copy number alterations are associated with resistance to NAC.

Pathological response post neoadjuvant therapy for locally advanced rectal cancer is an independent predictor of survival

AIM

Neoadjuvant treatment (NaT) for locally advanced rectal cancer prior to surgery has led to improved outcomes. However, the relationship between pathological response to NaT and survival is not entirely clear. The aim of this study was to assess the degree of pathological response to NaT on survival outcomes.

METHODS

Clinical and pathological data were collected from a prospectively maintained pathology database between 2005 and 2017. The primary outcome was the overall survival based on pathological response categorized as complete, good partial, partial and minimal. Univariate and multivariate analyses were conducted to identify variables predictive of survival. Cox proportional hazard ratios were used for survival.

RESULTS

A total of 596 patients had surgery following NaT for locally advanced rectal cancer. The median follow-up was 4.57 years (interquartile range 2.21-8.15 years). The overall survival for complete pathological response was 75.6% vs. 37.3% for minimal response (P < 0.001). The overall survival at the end of the study in the good partial vs. partial response groups was 58.9% vs. 39% (P < 0.001). On multivariate analysis, the degree of pathological response remains an independent variable for overall and disease-specific survival across all categories.

DISCUSSION

In addition to other pathological variables, the degree of pathological response to NaT is an independent predictor for survival outcomes. Future verification of these findings elsewhere could support NaT response being used for adjuvant therapy decision making.

Mucinous Adenocarcinoma of the Rectum: A Whole Genome Sequencing Study

Introduction

Mucinous adenocarcinoma of the rectum is an infrequently encountered histological subtype that is associated with an impaired response to chemoradiotherapy and a worse overall prognosis. A genomic profile analysis of mucinous rectal tumors has not yet been performed. The aim of this study was to comprehensively describe the burden of somatic mutations and copy number variation as well as perform mutational signature and microbial analysis of an in-house collected cohort of mucinous adenocarcinoma of the rectum.

Methods

Genomic DNA was extracted from 10 cases of mucinous rectal cancer and matched normal tissue. Whole genome sequencing (WGS) was carried out on these 10 cases and a comprehensive bioinformatic analysis was undertaken.

Results

The average number of SNVs, InDels and SVs in the cohort was 16,600, 1,855, and 120, respectively. A single case was MSI-H. KRAS mutations were found in 70% of cases while TP53 was mutated in only 40% of cases. CNA gain was identified on chromosomes 7, 8, 12, 13, and 20 while CNA loss was found on chromosomes 4, 8, 17, and 18 corresponding to oncogenes and tumor suppressor genes, respectively. Overall mucinous rectal cancers are more likely to be MSI-H and to have KRAS, BRAF, and PIK3CA mutations when compared to rectal adenocarcinoma NOS. Microbial analysis demonstrated an abundance of Fusobacterium nucleatum in tumor samples compared to normal tissue.

Conclusion

This study provides a detailed WGS analysis of 10 cases of mucinous rectal cancer. It demonstrates an important lesson in tumor biology in that histologically similar tumors can have extensive differences at the genomic level. This study is relevant as it raises important questions about the relationship between bacteria and malignancy.

Evaluation and Comparison of Predictive Value of Tumor Regression Grades according to Mandard and Becker in Locally Advanced Gastric Adenocarcinoma

Purpose

Tumor regression grade (TRG) has been widely used in gastrointestinal carcinoma to assess pathological responses to neoadjuvant chemotherapy (NCT). There are various standards without a consensus, and it is still unclear which kind of system has better predictive value. This study aims to investigate and compare the predictive ability of the Mandard and Becker TRGs in patients with locally advanced gastric cancer.

Materials and Methods

A total of 290 patients with locally advanced gastric adenocarcinoma who underwent NCT and curative surgery were studied. Survival analysis for overall survival (OS) and disease-free survival (DFS) were based on the Kaplan-Meier method and Cox proportional hazards method. Predictive values of TRGs and models were assessed by time-dependent receiver operating characteristic (ROC) curve, the area under the ROC curve (AUC), nomogram, and calibration curve.

Results

In multivariable analysis, the Mandard TRG was associated with OS (hazard ratio [HR], 1.806; p=0.026) and DFS (HR, 1.792; p=0.017). The Becker TRG was also related to OS (HR, 1.880; p=0.014) and DFS (HR, 1.919; p=0.006). The Mandard and Becker TRG AUCs for 5-year survival were 0.72 and 0.71, respectively. The whole models showed an increased predictive value, with AUCs of 0.85 and 0.86, respectively. There was no significant difference between the two TRGs and two models.

Conclusion

TRG was an independent predictor for survival, and there was no significant difference between these two systems.

Tumor Regression Grade Predicts Survival in Locally Advanced Gastric Adenocarcinoma Patients with Lymph Node Metastasis

Background

Tumor regression grade (TRG) is widely used in gastrointestinal carcinoma to evaluate pathological responses to neoadjuvant chemotherapy (NCT), but whether it is an independent prognostic factor is still controversial. The aim of this study is to investigate the value of TRG in locally advanced gastric adenocarcinoma patients who underwent NCT and curative resection.

Methods

Pathological regression was reevaluated according to the Mandard TRG. Survival curves were obtained by the Kaplan–Meier method, and differences in overall survival (OS) and disease-free survival (DFS) were compared using the log-rank test. Univariate and multivariate analyses for survival were based on the Cox proportional hazards method.

Results

In total, 290 patients were identified in our electronic database. In univariable analysis, TRG was associated with OS (HR = 3.822, P ≤ 0.001) and DFS (HR = 3.374, P ≤ 0.001). However, in multivariable analysis, TRG was not an independent factor for OS (P = 0.231) or DFS (P = 0.191). In the stratified analysis, TRG retrieved prognostic significance in patients with the metastasis of lymph node (HR = 2.034, P = 0.035 for OS; HR = 2.220, P = 0.016 for DFS), while not in patients with negative lymph node (P = 0.296 for OS; P = 0.172 for DFS).

Conclusions

TRG was not an independent predictor for survival, but the system regained its predicting significance in patients with lymph node metastasis.

Connection and distinction of tumor regression grading systems of gastrointestinal cancer

OBJECTIVES

As the neoadjuvant therapy has been successfully introduced in the treatment of gastrointestinal malignancies, the evaluation of therapeutic effectiveness is becoming increasingly important. Tumor-node-metastasis system has been widely applied. However, this system is mainly based on the location of residual tumor, but does not consider the amount of residual tumor. Tumor regression grading system, a quantitative method to assess the reaction of tumor to neoadjuvant treatment, could be used as a supplement to tumor-node-metastasis system and provide additional information on prognosis. To date, numerous gastrointestinal grading systems have been used in esophageal/esophagogastric junction carcinoma, gastric adenocarcinoma, colorectal cancer, and most of them were considered to associate with clinical outcomes.

MATERIALS AND METHODS

In this review, firstly, we expounded the importance of tumor regression grading systems, and summarized the histopathological changes after neoadjuvant therapy. Secondly, we introduced some commonly used gastrointestinal systems, as well as the relationships and nuance. Finally, we discussed pivotal issues about these systems. In this part, we explained the calculation methods based on grid points and square measures, discussed several factors leading to observer bias, containing the slice number and the grading tier number, and analyzed the factors that might affect clinical significance, covering anatomical location, the selection of survival index, and the tumor type.

RESULTS

Tumor regression grade systems could be divided into two main classifications, the relative amount of fibrosis and residual tumor, and the proportion of residual tumor in the tumor bed. However, the definitions of these systems were still need to be improved.

CONCLUSIONS

The tumor regression grading system is useful in evaluating tumor response to neoadjuvant therapy, but more work is needed to refine and unify the system.

Impact of preoperative chemotherapy on the histological response of patients with peritoneal metastases from colorectal cancer according to peritoneal regression grading score (PRGS) and TRG

BACKGROUND

This study evaluated the histologic response after preoperative systemic therapy (pST) using the Peritoneal Regression Grading Score (PRGS) and tumor regression grade (TRG) classifications for patients with peritoneal metastases (PM) from colorectal cancer (CRC).

METHODS

Twenty-three patients were selected from a prospective database of 196 patients who underwent CRS followed by HIPEC for synchronous PM from CRC. In all study patients, biopsies of the PM obtained before pST (during the first laparoscopy) and after pST (during cytoreductive surgery) were compared.

RESULTS

Complete (PRGS 1), Major (PRGS 2), Minor (PRGS 3) and no histological responses (PRGS 4) were obtained in 17,5%, 52% and 13% and 17,5% of patients, respectively. Major (TRG 1-2), partial (TRG3), and no (TRG4-5) histological tumor regression were observed in 61%, 9% and 30% of patients, respectively. Regardless of the classification applied, median OS was significantly higher in patients with a "complete or major" response than in those with a "minor/partial or no" response (54 vs. 26 months, p < 0.05).

CONCLUSIONS

The PRGS and TRG can be used in clinical practice to evaluate the histological response after pST. This study demonstrated that a complete histologic response of PM from CRC can be obtained after pST.

Multicenter Validation of Histopathologic Tumor Regression Grade After Neoadjuvant Chemotherapy in Muscle-invasive Bladder Carcinoma

Response classification after neoadjuvant chemotherapy in muscle-invasive bladder carcinoma is based on the TNM stage at radical cystectomy. We recently showed that histopathologic tumor regression grades (TRGs) add prognostic information to TNM. Our aim was to validate the prognostic significance of TRG in muscle-invasive bladder cancer in a multicenter setting. We enrolled 389 patients who underwent cisplatin-based chemotherapy before radical cystectomy in 8 centers between 2010 and 2016. Median follow-up was 2.2 years. TRG was determined in radical cystectomy specimens by local pathologists. Central pathology review was conducted in 20% of cases, which were randomly selected. The major response was defined as ≤pT1N0. The remaining patients were grouped into partial responders (≥ypT2N0-3 and TRG 2) and nonresponders (≥ypT2N0-3 and TRG 3). TRG was successfully determined in all cases, and interobserver agreement in central pathology review was high (κ=0.83). After combining TRG and TNM, 47%, 15%, and 38% of patients were major, partial, and nonresponders, respectively. Combination of TRG and TNM showed significant prognostic discrimination of overall survival (major responder: reference; partial responder: hazard ratio 3.5 [95% confidence interval: 1.8-6.8]; nonresponder: hazard ratio 6.1 [95% confidence interval: 3.6-10.3]). This discrimination was superior compared with TNM staging alone, supported by 2 goodness-of-fit criteria (P=0.041). TRG is a simple, reproducible histopathologic measurement of response to neoadjuvant chemotherapy in muscle-invasive bladder cancer. Integrating TRG with TNM staging resulted in significantly better prognostic stratification than TNM staging alone.

Improved Outcomes for Responders After Treatment with Induction Chemotherapy and Chemo(re)irradiation for Locally Recurrent Rectal Cancer

BACKGROUND

Despite improvements in the multimodality treatment for patients with locally recurrent rectal cancer (LRRC), oncological outcomes remain poor. This study evaluated the effect of induction chemotherapy and subsequent chemo(re)irradiation on the pathologic response and the rate of resections with clear margins (R0 resection) in relation to long-term oncological outcomes.

METHODS

All consecutive patients with LRRC treated in the Catharina Hospital Eindhoven who underwent a resection after treatment with induction chemotherapy and subsequent chemo(re)irradiation between January 2010 and December 2018 were retrospectively reviewed. Induction chemotherapy consisted of CAPOX/FOLFOX. Endpoints were pathologic response, resection margin and overall survival (OS), disease free survival (DFS), local recurrence free survival (LRFS), and metastasis free survival (MFS).

RESULTS

A pathologic complete response was observed in 22 patients (17%), a "good" response (Mandard 2-3) in 74 patients (56%), and a "poor" response (Mandard 4-5) in 36 patients (27%). An R0 resection was obtained in 83 patients (63%). The degree of pathologic response was linearly correlated with the R0 resection rate (p = 0.026). In patients without synchronous metastases, pathologic response was an independent predictor for LRFS, MFS, and DFS (p = 0.004, p = 0.003, and p = 0.024, respectively), whereas R0 resection was an independent predictor for LRFS and OS (p = 0.020 and p = 0.028, respectively).

CONCLUSIONS

Induction chemotherapy in addition to neoadjuvant chemo(re)irradiation is a promising treatment strategy for patients with LRRC with high pathologic response rates that translate into improved oncological outcomes, especially when an R0 resection has been achieved.

Clinical Significance of Fractional Anisotropy Measured in Peritumoral Edema as a Biomarker of Overall Survival in Glioblastoma: Evidence Using Correspondence Analysis

Introduction

Fractional anisotropy (FA), a diffusion tensor image (DTI) derived biomarker is related to invasion, infiltration, and extension of glioblastoma (GB). We aimed to evaluate FA values and their association with intervals of overall survival (OS).

Materials and Methods

Retrospective study conducted in 36 patients with GB included 23 (63.9%) males, 46 ± 14 y; and 13 (36.1%) females, 53 ± 13; followed up for 36 months. We measured FA at edema, enhancing rim, and necrosis. We created two categorical variables using levels of FA and intervals of OS to evaluate their relationships. Kaplan-Meier method and correspondence analysis evaluated the association between OS (grouped in 7 six-month intervals) and FA measurements.

Results

Median FA values were higher in healthy brain regions (0.351), followed by peritumoral edema (0.190), enhancing ring (0.116), and necrosis (0.071). Pair-wise comparisons among tumor regions showed a significant difference, P < 0.001. The median OS for all patients was 19.3 months; variations in the OS curves among subgroups was significant χ² (3) = 8.48, P = 0.037. Correspondence analysis showed a significant association between FA values in the edema region and the survival intervals χ² (18) = 30.996, P = 0.029.

Conclusions

Alternative multivariate assessment using correspondence analysis might supplement the traditional survival analysis in patients with GB. A close follow-up of the variability of FA in the peritumoral edema region is predictive of the OS within specific six-month interval subgroup. Further studies should focus on predictive models combining surgical and DTI biomarkers.

Organ-saving surgery for rectal cancer after neoadjuvant chemoradiation: Analysis of failures and long-term results

BACKGROUND

To analyze long-term results and risk of relapse in the clinical TNM stages II and III, mid-low rectal cancer patients (RC pts), treated with transanal local excision (LE) after major response to neoadjuvant chemoradiation (n-CRT).

METHODS

Thirty-two out of 345 extraperitoneal cT3-4 or N+ RC pts (9.3%) underwent LE.

INCLUSION CRITERIA

extraperitoneal RC, adenocarcinoma, ECOG Performance Status ≤2. Pts with distant metastases were excluded.

RESULTS

All pts showed histologically clear margins of resection and 81.2% were restaged ypT0/mic/1. Nine out of 32 (28.1%) pts relapsed: 7 (21.8%) showed a local recurrence, of which 5 (15.6%) at the endorectal suture, 1 (3.1%) pelvic and 1 (3.1%) mesorectal. Two pts (6.2%) relapsed distantly. Among the pT0/1, 11.5% relapsed vs 100% of the pT2 and pT4 ones. The six pts relapsing locally or in the mesorectal fat underwent a salvage total mesorectal excision surgery. The old patient with pelvic recurrence relapsed after 108 months and underwent a re-irradiation; the two pts with distant metastases were treated with chemotherapy followed by radical surgery.

CONCLUSIONS

Presently combined approach seems a valid option in major responders, confirming its potential curative impact in the ypT0/mic/1 pts. A strict selection of pts is basic to obtain favourable results.

Evaluating the Influence of Rain Event Characteristics on Rainfall Interception by Urban Trees Using Multiple Correspondence Analysis

Urban trees play an important role in the built environment, reducing the rainfall reaching the ground by rainfall interception. The amount of intercepted rainfall depends on the meteorological and vegetation characteristics. By applying the multiple correspondence analysis (MCA), we analysed the influence of rainfall amount, intensity and duration, the number of raindrops, the mean volume diameter (MVD), wind speed and direction on rainfall interception. The analysis was based on data from 176 events collected over more than three years of observations. Measurements were taken under birch (Betula pendula Roth.) and pine (Pinus nigra Arnold) trees located in an urban park in the city of Ljubljana, Slovenia. The results indicate that rainfall interception is influenced the most by rainfall amount and the number of raindrops. In general, the ratio of rainfall interception to gross rainfall decreases with longer and more intense rainfall events. The influence of the raindrop number depends also on their size (MVD), which is evident especially for the pine tree. For example, pine tree interception increases with smaller raindrops regardless of their number. In addition, MCA gives a new insight into the influence of wind characteristics, which was not visible using previous methods of data analysis (regression analysis, correlation matrices, regression trees, boosted regression trees). According to the nearby buildings, a wind corridor is sometimes created, decreasing rainfall interception by both tree species.

Circulating Biomarkers for Response Prediction of Rectal Cancer to Neoadjuvant Chemoradiotherapy

Rectal cancer response to neoadjuvant Chemoradiotherapy (pCRT) is highly variable. In fact, it has been estimated that only about 21 % of patients show pathologic Complete Response (pCR) after therapy, while in most of the patients a partial or incomplete tumour regression is observed. Consequently, patients with a priori chemoradioresistant tumour should not receive the treatment, which is associated with substantial adverse effects and does not guarantee any clinical benefit. For Locally Advanced Rectal Cancer Patients (LARC), a standardized neoadjuvant treatment protocol is applied, the identification and the usefulness of prognostic or predictive biomarkers can improve the antitumoural treatment strategy, modifying the sequence, dose, and combination of radiotherapy, chemotherapy and surgical resection. For these reasons, a growing number of studies are actually focussed on the discovery and investigation of new predictive biomarkers of response to pCRT. In this review, we have selected the most recent literature (2012-2017) regarding the employment of blood-based biomarkers potentially predicting pCR in LARC patients and we have critically discussed them to highlight their real clinical benefit and the current limitations of the proposed methodological approaches.

The mutational landscape of recurrent versus nonrecurrent human papillomavirus-related oropharyngeal cancer

BACKGROUND

Human papillomavirus-related (HPV-related) oropharyngeal squamous cell carcinomas (OPSCCs) have an excellent response rate to platinum-based chemoradiotherapy. Genomic differences between primary HPV-related OPSCCs that do or do not recur are unknown. Furthermore, it is unclear if HPV-related OPSCCs that recur share a genomic landscape with HPV-negative head and neck cancers (HNCs).

METHODS

We utilized whole exome sequencing to analyze somatic nucleotide (SNVs) and copy number variants (CNVs) among a unique set of 51 primary HPV-related OPSCCs, including 35 that did not recur and 16 that recurred. We evaluated 12 metachronous recurrent OPSCCs (7 with paired primary OPSCCs) and 33 primary HPV-unrelated oral cavity and OPSCCs.

RESULTS

KMT2D was the most frequently mutated gene among primary HPV-related OPSCCs (n = 51; 14%) and among metachronous recurrent OPSCCs (n = 12; 42%). Primary HPV-related OPSCCs that recurred shared a genomic landscape with primary HPV-related OPSCCs that did not recur. However, TSC2, BRIP1, NBN, and NFE2L2 mutations occurred in primary OPSCCs that recurred but not in those that did not recur. Moreover, primary HPV-related OPSCCs that recur harbor features of HPV-unrelated HNCs, notably including MAPK, JAK/STAT, and differentiation signaling pathway aberrations. Metachronous recurrent OPSCCs shared a genomic landscape with HPV-unrelated HNCs, including a high frequency of TP53, CASP8, FAT1, HLA-A, AJUBA, and NSD1 genomic alterations.

CONCLUSION

Overall, primary HPV-related OPSCCs that recur share a genomic landscape with nonrecurrent OPSCCs. Metachronous recurrent OPSCCs share genomic features with HPV-negative HNCs. These data aim to guide future deescalation endeavors and functional experiments.

FUNDING

This study is supported by the American Cancer Society (RSG TBG-123653), funding support for RAH (T32DC00018, Research Training in Otolaryngology, University of Washington), funds to EM from Seattle Translational Tumor Research (Fred Hutchinson Cancer Research Center), and center funds from the Fred Hutchinson Cancer Research Center to EM. UD is supported by the Department of Veterans Affairs, Biomedical Laboratory Research and Development (BLR&D), grant IO1-oo23456, and funds from the Pittsburgh Foundation and PNC Foundation.