Clinical and molecular practice of European thoracic pathology laboratories during the COVID-19 pandemic. The past and the near future.

BACKGROUND: This study evaluated the consequences in Europe of the COVID-19 outbreak on pathology laboratories orientated toward the diagnosis of thoracic diseases. MATERIALS AND METHODS: A survey was sent to 71 pathology laboratories from 21 European countries. The questionnaire requested information concerning the organization of biosafety, the clinical and molecular pathology, the biobanking, the workload, the associated research into COVID-19, and the organization of education and training during the COVID-19 crisis, from 15 March to 31 May 2020, compared with the same period in 2019. RESULTS: Questionnaires were returned from 53/71 (75%) laboratories from 18 European countries. The biosafety procedures were heterogeneous. The workload in clinical and molecular pathology decreased dramatically by 31% (range, 3%-55%) and 26% (range, 7%-62%), respectively. According to the professional category, between 28% and 41% of the staff members were not present in the laboratories but did teleworking. A total of 70% of the laboratories developed virtual meetings for the training of residents and junior pathologists. During the period of study, none of the staff members with confirmed COVID-19 became infected as a result of handling samples. CONCLUSIONS: The COVID-19 pandemic has had a strong impact on most of the European pathology laboratories included in this study. Urgent implementation of several changes to the organization of most of these laboratories, notably to better harmonize biosafety procedures, was noted at the onset of the pandemic and maintained in the event of a new wave of infection occurring in Europe.

ESMO recommendations on the standard methods to detect NTRK fusions in daily practice and clinical research.

BACKGROUND: NTRK1, NTRK2 and NTRK3 fusions are present in a plethora of malignancies across different histologies. These fusions represent the most frequent mechanism of oncogenic activation of these receptor tyrosine kinases, and biomarkers for the use of TRK small molecule inhibitors. Given the varying frequency of NTRK1/2/3 fusions, crucial to the administration of NTRK inhibitors is the development of optimal approaches for the detection of human cancers harbouring activating NTRK1/2/3 fusion genes. MATERIALS AND METHODS: Experts from several Institutions were recruited by the European Society for Medical Oncology (ESMO) Translational Research and Precision Medicine Working Group (TR and PM WG) to review the available methods for the detection of NTRK gene fusions, their potential applications, and strategies for the implementation of a rational approach for the detection of NTRK1/2/3 fusion genes in human malignancies. A consensus on the most reasonable strategy to adopt when screening for NTRK fusions in oncologic patients was sought, and further reviewed and approved by the ESMO TR and PM WG and the ESMO leadership. RESULTS: The main techniques employed for NTRK fusion gene detection include immunohistochemistry, fluorescence in situ hybridization (FISH), RT-PCR, and both RNA-based and DNA-based next generation sequencing (NGS). Each technique has advantages and limitations, and the choice of assays for screening and final diagnosis should also take into account the resources and clinical context. CONCLUSION: In tumours where NTRK fusions are highly recurrent, FISH, RT-PCR or RNA-based sequencing panels can be used as confirmatory techniques, whereas in the scenario of testing an unselected population where NTRK1/2/3 fusions are uncommon, either front-line sequencing (preferentially RNA-sequencing) or screening by immunohistochemistry followed by sequencing of positive cases should be pursued.

ESMO recommendations on microsatellite instability testing for immunotherapy in cancer, and its relationship with PD-1/PD-L1 expression and tumour mutational burden: a systematic review-based approach.

BACKGROUND: Cancers with a defective DNA mismatch repair (dMMR) system contain thousands of mutations most frequently located in monomorphic microsatellites and are thereby defined as having microsatellite instability (MSI). Therefore, MSI is a marker of dMMR. MSI/dMMR can be identified using immunohistochemistry to detect loss of MMR proteins and/or molecular tests to show microsatellite alterations. Together with tumour mutational burden (TMB) and PD-1/PD-L1 expression, it plays a role as a predictive biomarker for immunotherapy. METHODS: To define best practices to implement the detection of dMMR tumours in clinical practice, the ESMO Translational Research and Precision Medicine Working Group launched a collaborative project, based on a systematic review-approach, to generate consensus recommendations on the: (i) definitions related to the concept of MSI/dMMR; (ii) methods of MSI/dMMR testing and (iii) relationships between MSI, TMB and PD-1/PD-L1 expression. RESULTS: The MSI-related definitions, for which a consensus frame-work was used to establish definitions, included: 'microsatellites', 'MSI', 'DNA mismatch repair' and 'features of MSI tumour'. This consensus also provides recommendations on MSI testing; immunohistochemistry for the mismatch repair proteins MLH1, MSH2, MSH6 and PMS2 represents the first action to assess MSI/dMMR (consensus with strong agreement); the second method of MSI/dMMR testing is represented by polymerase chain reaction (PCR)-based assessment of microsatellite alterations using five microsatellite markers including at least BAT-25 and BAT-26 (strong agreement). Next-generation sequencing, coupling MSI and TMB analysis, may represent a decisive tool for selecting patients for immunotherapy, for common or rare cancers not belonging to the spectrum of Lynch syndrome (very strong agreement). The relationships between MSI, TMB and PD-1/PD-L1 expression are complex, and differ according to tumour types. CONCLUSIONS: This ESMO initiative is a response to the urgent questions raised by the growing success of immunotherapy and provides also important insights on the relationships between MSI, TMB and PD-1/PD-L1.

National multicentric evaluation of quality of pathology reports for rectal cancer in France in 2016.

The quality of pathologic assessment of rectal cancer specimens is crucial for treatment efficiency and survival. The Royal College of Pathologists (RCP) recommends evaluating the quality of the pathology report in routine practice using three quality indicators (QIs): the number of lymph nodes (LNs) analyzed (≥ 12), the rate of venous invasion (VI ≥ 30%), and peritoneal involvement (pT4a ≥ 10%). In this study, we evaluated the three QIs of the French national pathology reports and compared them with British guidelines and assessed the influence of neoadjuvant radiochemotherapy on QIs. From January 1 to December 31, 2016, all pathology reports for rectal adenocarcinoma were collected from French departments. Neoadjuvant radiochemotherapy included long-course radiotherapy with concomitant 5-FU-based chemotherapy. A total of 983 rectal cancer pathology reports were evaluated. A median of 15 LNs were analyzed and 81% of centers had ≥ 12 LNs. The rate of VI was 30% and 41% of centers had ≥ 30% VI. The rate of pT4a was 4% and 18% of centers reported ≥ 10% pT4a. None of the centers reached the threshold for the three QIs. All three QIs were lower after radiochemotherapy compared to surgery alone. In conclusion, in French routine practice, the values of two of the three QIs (LNs analyzed and VI) were globally in line with RCP guidelines. However, the rate of pT4a was very low, particularly after radiochemotherapy, suggesting its low value in rectal cancer.

Clinical and molecular characterisation of hereditary and sporadic metastatic colorectal cancers harbouring microsatellite instability/DNA mismatch repair deficiency.

BACKGROUND: Patients treated with chemotherapy for microsatellite unstable (MSI) and/or mismatch repair deficient (dMMR) cancer metastatic colorectal cancer (mCRC) exhibit poor prognosis. We aimed to evaluate the relevance of distinguishing sporadic from Lynch syndrome (LS)-like mCRCs. PATIENTS AND METHODS: MSI/dMMR mCRC patients were retrospectively identified in six French hospitals. Tumour samples were screened for MSI, dMMR, RAS/RAF mutations and MLH1 methylation. Sporadic cases were molecularly defined as those displaying MLH1/PMS2 loss of expression with BRAFV600E and/or MLH1 hypermethylation and no MMR germline mutation. RESULTS: Among 129 MSI/dMMR mCRC patients, 81 (63%) were LS-like and 48 (37%) had sporadic tumours; 22% of MLH1/PMS2-negative mCRCs would have been misclassified using an algorithm based on local medical records (age, Amsterdam II criteria, BRAF and MMR statuses when locally tested), compared to a systematical assessment of MMR, BRAF and MLH1 methylation statuses. In univariate analysis, parameters associated with better overall survival were age (P < 0.0001), metastatic resection (P = 0.001) and LS-like mCRC (P = 0.01), but not BRAFV600E. In multivariate analysis, age (hazard ratio (HR) = 3.19, P = 0.01) and metastatic resection (HR = 4.2, P = 0.001) were associated with overall survival, but not LS. LS-like patients were associated with more frequent liver involvement, metastatic resection and better disease-free survival after metastasectomy (HR = 0.28, P = 0.01). Median progression-free survival of first-line chemotherapy was similar between the two groups (4.2 and 4.2 months; P = 0.44). CONCLUSIONS: LS-like and sporadic MSI/dMMR mCRCs display distinct natural histories. MMR, BRAF mutation and MLH1 methylation testing should be mandatory to differentiate LS-like and sporadic MSI/dMMR mCRC, to determine in particular whether immune checkpoint inhibitors efficacy differs in these two populations.

Immunohistochemical evaluation of two antibodies against PD-L1 and prognostic significance of PD-L1 expression in epithelioid peritoneal malignant mesothelioma: A RENAPE study.

BACKGROUND: Epithelioid peritoneal malignant mesothelioma (EPMM) is the most common subtype of this aggressive tumor. We compared two antibodies against PD-L1, a recent theranostic biomarker, and evaluated the prognostic value of PD-L1 expression by mesothelial and immune cells in EPMM. METHODS: Immunohistochemistry was performed on 45 EPMM. Clinical and pathological data were extracted from the RENAPE database. Using E1L3N and SP142 clones, inter-observer agreement, PD-L1 expression by mesothelial and immune cells and inter-antibody agreement were evaluated. The prognostic relevance of PD-L1 expression was evaluated in 39 EPMM by univariate and multivariate analysis of overall survival (OS) and progression-free survival (PFS). RESULTS: Inter-observer agreement on E1L3N immunostaining was moderate for mesothelial and immune cells, and fair for mesothelial and poor for immune cells using SP142. Using E1L3N, 31.1% of mesothelial and 15.6% of immune cells expressed PD-L1, and 22.2% of mesothelial and 26.7% of immune cells using SP142. Inter-antibody agreement was moderate. In most positive cases, 1-5% of tumor cells were positive. Using E1L3N, PD-L1 expression by lymphocytes was associated with better OS and PFS by both univariate and multivariate analysis. Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy predicted better prognosis than other treatments. Solid subtype was an independent prognostic factor for worse OS. CONCLUSION: E1L3N appeared easier to use than SP142 to evaluate PD-L1 expression. A minority of EPMM expressed PD-L1, and only a few cells were positive. PD-L1 expression by immune cells evaluated with E1L3N was an independent prognostic factor in EPMM.

Antibody targeting of claudin-1 as a potential colorectal cancer therapy.

BACKGROUND: Metastatic colorectal cancer (mCRC) is one of the major causes of cancer-related death. Despite the substantial progress in mCRC management, it remains important to identify new therapeutic options and biological markers for personalized medicine. Here, we investigated the expression of claudin-1 (CLDN1), a major tight junction transmembrane protein, in the different colorectal cancer (CRC) molecular subtypes and then assessed the anti-tumor effect of a new anti-CLDN1 monoclonal antibody (mAb). METHODS: Gene expression profiling and immunochemistry analysis of normal and tumor tissue samples from patients with stage IV CRC were used to determine CLDN1 gene expression. Then, the 6F6 mAb against CLDN1 extracellular part was generated. Its effect on CRC cell cycle, proliferation, survival and migration was assessed in vitro, using a 3D cell culture system, flow cytometry, clonogenic and migration assays. In vivo, 6 F6 mAb efficacy was evaluated in nude mice after subcutaneous xenografts or intrasplenic injection of CRC cells. RESULTS: Compared with normal mucosa where it was almost exclusively cytoplasmic, in CRC samples CLDN1 was overexpressed (p < 0.001) and mainly localized at the membrane. Moreover, it was differentially expressed in the various CRC molecular subtypes. The strongest expressions were found in the consensus molecular subtype CMS2 (p < 0.001), the transit-ampliflying (p < 0.001) and the C5 subtypes (p < 0.001). Lower CLDN1 expression predicted a better outcome in the molecular subtypes C3 and C5 (p = 0.012 and p = 0.004, respectively). CLDN1 targeting with the 6 F6 mAb led to reduction of survival, growth and migration of CLDN1-positive cells. In preclinical mouse models, the 6F6 mAb decreased tumor growth and liver metastasis formation. CONCLUSION: Our data indicate that CLDN1 targeting with an anti-CLDN1 mAb results in decreased growth and survival of CRC cells. This suggests that CLDN1 could be a new potential therapeutic target.

Molecular subtypes of metastatic colorectal cancer are associated with patient response to irinotecan-based therapies.

BACKGROUND: Currently, metastatic colorectal cancer is treated as a homogeneous disease and only RAS mutational status has been approved as a negative predictive factor in patients treated with cetuximab. The aim of this study was to evaluate if recently identified molecular subtypes of colon cancer are associated with response of metastatic patients to first-line therapy. PATIENTS AND METHODS: We collected and analysed 143 samples of human colorectal tumours with complete clinical annotations, including the response to treatment. Gene expression profiling was used to classify patients in three to six classes using four different molecular classifications. Correlations between molecular subtypes, response to treatment, progression-free and overall survival were analysed. RESULTS: We first demonstrated that the four previously described molecular classifications of colorectal cancer defined in non-metastatic patients also correctly classify stage IV patients. One of the classifications is strongly associated with response to FOLFIRI (P=0.003), but not to FOLFOX (P=0.911) and FOLFIRI + Bevacizumab (P=0.190). In particular, we identify a molecular subtype representing 28% of the patients that shows an exceptionally high response rate to FOLFIRI (87.5%). These patients have a two-fold longer overall survival (40.1 months) when treated with FOLFIRI, as first-line regimen, instead of FOLFOX (18.6 months). CONCLUSIONS: Our results demonstrate the interest of molecular classifications to develop tailored therapies for patients with metastatic colorectal cancer and a strong impact of the first-line regimen on the overall survival of some patients. This however remains to be confirmed in a large prospective clinical trial.

The RENAPE observational registry: rationale and framework of the rare peritoneal tumors French patient registry.

BACKGROUND: Rare peritoneal cancers represent complex clinical situations requiring a specific and multidisciplinary management. Because of their rarity, lack of awareness and knowledge often leads to diagnostic delays and misdiagnosis. And patients are not systematically referred to expert centers as they should be. Clinicians and researchers also face unique challenges with these rare cancers, because it is hard to conduct adequately powered, controlled trials in such small patient population. This is how an observational patient registry constitutes a key instrument for the development of epidemiological and clinical research in the field of these rare cancers. It is the appropriate tool to pool scarce data for epidemiological research and to assess the impact of diagnostic and therapeutic strategies. We aimed to provide the outlines and the framework of the RENAPE observational registry and share our experience in the establishment of a national patient registry. RESULTS: The RENAPE observational registry has been launched in 2010 thanks to institutional supports. It concerns only patients with a histological diagnosis confirming a peritoneal surface malignancy. A web secured clinical database has been implemented based on data management procedures according to the principles of international recommendations and regulatory statements. A virtual tumor bank is linked in order to the conduct translational studies. Specialized working groups have been established to continuously upgrade and evolve the common clinical and histological data elements following the last classifications and clinical practices. They contribute also to standardize clinical assessment and homogenize practices. CONCLUSIONS: The RENAPE Registry may improve awareness and understanding of the rare peritoneal tumors into the incidence, prevalence, recurrence, survival and mortality rates, as well as treatment practices thereby enabling therapeutic intervention to be evaluated and ultimately optimized. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02834169.

Outcomes of special histotypes of breast cancer after adjuvant endocrine therapy with letrozole or tamoxifen in the monotherapy cohort of the BIG 1-98 trial.

BACKGROUND: We investigated the outcomes of postmenopausal women with hormone receptor-positive, early breast cancer with special histotypes (mucinous, tubular, or cribriform) enrolled in the monotherapy cohort of the BIG 1-98 trial. PATIENTS AND METHODS: The intention-to-treat BIG 1-98 monotherapy cohort (5 years of therapy with tamoxifen or letrozole) included 4922 women, of whom 4091 had central pathology review. Histotype groups were defined as: mucinous (N = 100), tubular/cribriform (N = 83), ductal (N = 3257), and other (N = 651). Of 183 women with either mucinous or tubular/cribriform tumors, 96 were randomly assigned to letrozole and 87 to tamoxifen. Outcomes assessed were disease-free survival (DFS), overall survival (OS), breast cancer-free interval (BCFI), and distant recurrence-free interval (DRFI). Median follow-up in the analytic cohort was 8.1 years. RESULTS: Women with tubular/cribriform breast cancer had the best outcomes for all end points compared with the other three histotypes, and had less breast cancer recurrence (97.5% 5-year BCFI) than those with mucinous (93.5%), ductal (88.9%), or other (89.9%) histotypes. Patients with mucinous or tubular/cribriform carcinoma had better DRFI (5-year rates 97.8% and 98.8%, respectively) than those with ductal (90.9%) or other (92.1%) carcinomas. Within the subgroup of women with special histotypes, we observed a nonsignificant increase in the hazard of breast cancer recurrence with letrozole [hazard (letrozole versus tamoxifen): 3.31, 95% confidence interval 0.94-11.7; P = 0.06]. CONCLUSIONS: Women with mucinous or tubular/cribriform breast cancer have better outcomes than those with other histotypes, although the observation is based on a limited number of events. In postmenopausal women with these histotypes, the magnitude of the letrozole advantage compared with tamoxifen may not be as large in patients with mucinous or tubular/cribriform disease. CLINICALTRIALSGOV: NCT00004205.

Professional risks when carrying out cytoreductive surgery for peritoneal malignancy with hyperthermic intraperitoneal chemotherapy (HIPEC): A French multicentric survey.

BACKGROUND: Over the last two decades, many surgical teams have developed programs to treat peritoneal carcinomatosis with extensive cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC). Currently, there are no specific recommendations for HIPEC procedures concerning environmental contamination risk management, personal protective equipment (PPE), or occupational health supervision. METHODS: A survey of the institutional practices among all French teams currently performing HIPEC procedures was carried out via the French network for the treatment of rare peritoneal malignancies (RENAPE). RESULTS: Thirty three surgical teams responded, 14 (42.4%) which reported more than 10 years of HIPEC experience. Some practices were widespread, such as using HIPEC machine approved by the European Community (100%), individualized or centralized smoke evacuation (81.8%), "open" abdominal coverage during perfusion (75.8%), and maintaining the same surgeon throughout the procedure (69.7%). Others were more heterogeneous, including laminar flow air circulation (54.5%) and the provision of safety protocols in the event of perfusate spills (51.5%). The use of specialized personal protective equipment is ubiquitous (93.9%) but widely variable between programs. CONCLUSION: Protocols regarding cytoreductive surgery/HIPEC and the associated professional risks in France lack standardization and should be established.

Utility of reassessment after neoadjuvant therapy and difficulties in interpretation.

We describe the main tools for MR assessment of the response of rectal cancer tumors after chemotherapy, before surgery. In locally advanced cases of rectal and lower rectal cancer, MR is useful in allowing the treatment strategy to be adjusted, enabling conservative surgery to be performed if the patient responds well. The different types of response (fibrous, desmoplastic and colloid), their appearances and difficulties in MR interpretation are described. We describe the features and performance of MR after neoadjuvant therapy for T and N staging, assessment of circumferential resection margin and diffusion weighted imaging. Quantitative (change in tumor volume) and qualitative (grade of tumor response) MR assessment can distinguish good responders from poor responders.

Sorafenib and irinotecan (NEXIRI) as second- or later-line treatment for patients with metastatic colorectal cancer and KRAS-mutated tumours: a multicentre Phase I/II trial.

BACKGROUND: This trial evaluated the feasibility and efficacy of combined sorafenib and irinotecan (NEXIRI) as second- or later-line treatment of patients with KRAS-mutated metastatic colorectal cancer (mCRC), who had progressed after irinotecan-based chemotherapy. METHODS: In Phase I, in a 3+3 dose escalation schedule, patients received irinotecan (125, 150 or 180 mg m(-2) every 2 weeks), in combination with 400 mg sorafenib b.d. The primary end point was the maximum-tolerated dose of irinotecan. In Phase II, the primary end point was disease control rate (DCR). Secondary end points were progression-free survival (PFS), overall survival (OS) and toxicity. RESULTS: Phase I included 10 patients (median age 63 (49-73)); no dose-limiting toxicity was seen. In Phase II, 54 patients (median age 60 (43-80) years) received irinotecan 180 mg m(-)(2) every 2 weeks with sorafenib 400 mg b.d. Nine patients (17%) remained on full-dose sorafenib. The DCR was 64.9% (95% CI, 51-77). Median PFS and OS were 3.7 (95% CI, 3.2-4.7) and 8.0 (95% CI, 4.8-9.7) months, respectively. Toxicities included Grade 3 diarrhoea (37%), neutropenia (18%), hand-foot syndrome (13%) and Grade 4 neutropenia (17%). CONCLUSION: The NEXIRI regimen showed promising activity as second- or later-line treatment in this heavily pretreated mCRC population (ClinicalTrials.gov NCT00989469).

The colorectal cancer stem-like cell hypothesis: a pathologist's point of view.

Colorectal cancer is the fourth most common cancer in men and the third most common cancer in women worldwide. The partial failure of classic therapeutic options makes scientists to doubt the efficacy of systemic treatments in targeting the essential cell populations and achieving cure as a final goal. Overgrowing data suggest that cancer is a disease closely linked to stem cells (SCs). It is well known that the first identification of cancer stem-like cells in acute myeloid leukaemia was soon followed by similar results in solid malignancies, including colorectal cancer, and the classic model for colon carcinogenesis supports the development of sudden mutations that will lead to the activation or inactivation of certain oncogenes or tumor suppressors. Thus, this process may go on for years before the first symptoms and the only cells able to withstand for many years, avoid apoptosis and have a high regenerative capacity are the progenitor cells found at the lower part of colon crypts. A more profound study of the mechanisms and molecular signalling pathways that control the basic characteristics of SCs, such as asymmetrical division or self-renewal, may help comprehend the basic mechanisms of cancer genesis and progression. This will result in the development of new therapeutic agents that may target chemoresistant cell populations and improve the therapeutic results. In the current review we point out the importance of cancer stem-like cells in colorectal oncology from a pathologist's point of view, stating the obvious correlation between histology, embryology and surgical pathology.

A refined molecular taxonomy of breast cancer.

The current histoclinical breast cancer classification is simple but imprecise. Several molecular classifications of breast cancers based on expression profiling have been proposed as alternatives. However, their reliability and clinical utility have been repeatedly questioned, notably because most of them were derived from relatively small initial patient populations. We analyzed the transcriptomes of 537 breast tumors using three unsupervised classification methods. A core subset of 355 tumors was assigned to six clusters by all three methods. These six subgroups overlapped with previously defined molecular classes of breast cancer, but also showed important differences, notably the absence of an ERBB2 subgroup and the division of the large luminal ER+ group into four subgroups, two of them being highly proliferative. Of the six subgroups, four were ER+/PR+/AR+, one was ER-/PR-/AR+ and one was triple negative (AR-/ER-/PR-). ERBB2-amplified tumors were split between the ER-/PR-/AR+ subgroup and the highly proliferative ER+ LumC subgroup. Importantly, each of these six molecular subgroups showed specific copy-number alterations. Gene expression changes were correlated to specific signaling pathways. Each of these six subgroups showed very significant differences in tumor grade, metastatic sites, relapse-free survival or response to chemotherapy. All these findings were validated on large external datasets including more than 3000 tumors. Our data thus indicate that these six molecular subgroups represent well-defined clinico-biological entities of breast cancer. Their identification should facilitate the detection of novel prognostic factors or therapeutical targets in breast cancer.

Clinical impact of lymph node status in rectal cancer.

Lymph node status at the time of diagnosis remains one of the principal indicators of prognosis in patients with rectal cancer. Involvement of loco-regional lymph nodes is relevant to surgical and clinical oncologists and continues to impact significantly upon local and systemic management strategies, in both neo-adjuvant and adjuvant settings. In this review, the clinical impact of lymph node status in the surgical management of rectal cancer is considered, with particular reference to the significance of lymphadenectomy and the potential implications for rectal tumours amenable to trans-anal excision. Current standards of care are reviewed and the extent to which the determination of lymph node status influences oncological decisions regarding neo-adjuvant and adjuvant therapies are discussed with areas of controversy highlighted.

A large-scale candidate gene approach identifies SNPs in SOD2 and IL13 as predictive markers of response to preoperative chemoradiation in rectal cancer.

Neoadjuvant radiochemotherapy followed by total mesorectal excision is now the standard treatment for locally advanced rectal cancer. However, tumor response to chemoradiation varies widely among individuals and cannot be determined before the final pathologic evaluation. The aim of this study was to identify germline genetic markers that could predict sensitivity or resistance to preoperative radiochemotherapy (RT-CT) in rectal cancer. We evaluated the predictive value of 128 single-nucleotide polymorphisms (SNPs) in 71 patients preoperatively treated by RT-CT. The selected SNPs were distributed over 76 genes that are involved in various cellular processes such as DNA repair, apoptosis, proliferation or immune response. The SNPs superoxide dismutase 2 (SOD2) rs4880 (P=0.005) and interleukin-13 (IL13) rs1800925 (P=0.0008) were significantly associated with tumor response to chemoradiation. These results reinforce the idea of using germline polymorphisms for personalized treatment.