Prediction of response to chemoradiation in rectal cancer by a gene polymorphism in the epidermal growth factor receptor promoter region

Genome-scale CRISPR-Cas9 knockout screening in nasopharyngeal carcinoma for radiosensitive and radioresistant genes

BACKGROUND

Genome-scale CRISPR-Cas9 knockout screening may provide new insights into the mechanism underlying clinical radioresistance in nasopharyngeal carcinoma (NPC), which is remain largely unknown. Our objective was to screen the functional genes associated with radiosensitivity and radioresistance in NPC, laying a foundation for further research on its functional mechanismand.

METHODS

CRISPR-Cas9 library lentivirus screening in radiation-treated NPC cells was combined with second-generation sequence technology to identify functional genes, which were further validated in radioresistant NPC cells and patient tissues.

RESULTS

Eleven radiosensitive and radioresistant genes were screened. Among these genes, the expression of FBLN5, FAM3C, MUS81, and DNAJC17 were significantly lower and TOMM20, CDKN2AIP, SNX22, and SP1 were higher in the radioresistant NPC cells (C666-1R, 5-8FR) (p < 0.05). CALD1 was highly expressed in C666-1R. Furthermore, we found knockout of FBLN5, FAM3C, MUS81 and DNAJC17 promoted the proliferation of NPC cells, while CDKN2AIP and SP1 had the opposed results (p < 0.05). This result was verified in NPC patient tissues. Meanwhile, KEGG analysis showed that the Fanconi anemia pathway and the TGF-β signaling pathway possibly contributed to radiosensitivity or radioresistance in NPC.

CONCLUSIONS

Nine genes involved in the radiosensitivity or radioresistance of NPC: four genes for radiosensitivity (FBLN5, FAM3C, MUS81, and DNAJC17), two genes for radioresistance (CDKN2AIP, SP1), two potential radioresistant genes (TOMM20, SNX22), and a potential radiosensitive gene (CALD1). Genome-scale CRISPR-Cas9 knockout screening for radiosensitive and radioresistant genes in NPC may provide new insights into the mechanisms underlying clinical radioresistance to improve the efficacy of radiotherapy for NPC.

Circulating Biomarkers in Predicting Pathological Response to Neoadjuvant Therapy for Colorectal Cancer

Circulating biomarkers show promise in the management of many cancers. They have become the novel non-invasive approach to complement the current strategies in colorectal cancer (CRC) management. Their ability in guiding diagnosis, evaluating response to treatment, screening and prognosis is phenomenal, especially when it comes to their minimally invasive nature. These “liquid biopsies,” which show potential for replacing invasive surgical biopsies, provide useful information on the primary and metastatic disease by providing an insight into cancer biology. Analysis of blood and body fluids for circulating tumour DNA (ctDNA), carcinoembryonic antigen (CEA), circulating tumour cells (CTC), or circulating micro RNA (miRNA) shows potential for improving CRC management. Recognizing a predictive model to assess response to neoadjuvant chemotherapy would help in better patient selection. This review was conducted with the aim of outlining the use of circulatory biomarkers in current practice and their effectiveness in the management of patients having CRC with a focus on response to neoadjuvant therapy.

Polymorphisms in EGFR Gene Predict Clinical Outcome in Unresectable Non-Small Cell Lung Cancer Treated with Radiotherapy and Platinum-Based Chemoradiotherapy

For non-small cell lung cancer (NSCLC), radiotherapy (RT) and platinum-based chemotherapy (CHT) are among the main treatment options. On the other hand, radioresistance and cytotoxic drug resistance are common causes of failure. The epidermal growth factor receptor (EGFR) plays an important role in radioresponse and therapy resistance. We hypothesized that single nucleotide polymorphisms (SNPs) in the EGFR gene might affect individual sensitivity to these treatments, and thus, therapy outcome and prognosis. The association between functional EGFR SNPs and overall (OS), locoregional recurrence-free (LFRS), and metastasis-free (MFS) survival was examined in 436 patients with unresectable NSCLC receiving RT and platinum-based CHTRT. In a multivariate analysis, the rs712830 CC homozygotes showed reduced OS in the whole group (p = 0.039) and in the curative treatment subset (p = 0.047). The rs712829 TT genotype was strongly associated with decreased LRFS (p = 0.006), and the T-C haplotype was a risk factor for locoregional recurrence in our patients (p = 0.003). The rs2227983 GG alone and in combination with rs712829 T was an indicator of unfavorable LRFS (p = 0.028 and 0.002, respectively). Moreover, significant independent effects of these SNPs on OS, LRFS, and MFS were observed. Our results demonstrate that inherited EGFR gene variants may predict clinical outcomes in NSCLC treated with DNA damage-inducing therapy.

Germline and Somatic Pharmacogenomics to Refine Rectal Cancer Patients Selection for Neo-Adjuvant Chemoradiotherapy

Neoadjuvant chemoradiotherapy (nCRT) followed by radical surgery is the standard of care for patients with Locally Advanced Rectal Cancer (LARC). Current selection for nCRT is based on clinical criteria regardless of any molecular marker. Pharmacogenomics may be a useful strategy to personalize and optimize nCRT in LARC. This review aims to summarize the most recent and relevant findings about the role of germline and somatic pharmacogenomics in the prediction of nCRT outcome in patients with LARC, discussing the state of the art of their application in the clinical practice. A systematic literature search of the PubMed database was completed to identify relevant English-language papers published up to January 2020. The chemotherapeutic backbone of nCRT is represented by fluoropyrimidines, mainly metabolized by DPD (Dihydro-Pyrimidine Dehydrogenase, DPYD). The clinical impact of testing DPYD*2A, DPYD*13, c.2846A > T and c.1236G > A-HapB3 before a fluoropyrimidines administration to increase treatment safety is widely acknowledged. Other relevant target genes are TYMS (Thymidylate Synthase) and MTHFR (Methylene-Tetrahydro-Folate Reductase), whose polymorphisms were mainly studied as potential markers of treatment efficacy in LARC. A pivotal role of a TYMS polymorphism in the gene promoter region (rs34743033) was reported and was pioneeringly used to guide nCRT treatment in a phase II study. The pharmacogenomic analysis of other pathways mostly involved in the cellular response to radiation damage, as the DNA repair and the activation of the inflammatory cascade, provided less consistent results. A high rate of somatic mutation in genes belonging to PI3K (Phosphatidyl-Inositol 3-Kinase) and MAPK (Mitogen-Activated Protein Kinase) pathways, as BRAF (V-raf murine sarcoma viral oncogene homolog B1), KRAS (Kirsten Rat Sarcoma viral oncogene homolog), NRAS (Neuroblastoma RAS viral (v-ras) oncogene homolog), PIK3CA (Phosphatidyl-Inositol-4,5-bisphosphate 3-Kinase, Catalytic Subunit Alpha), as well as TP53 (Tumor Protein 53) was reported in LARC. Their pharmacogenomic role, already defined in colorectal cancer, is under investigation in LARC with promising results concerning specific somatic mutations in KRAS and TP53, as predictors of tumor response and prognosis. The availability of circulating tumor DNA in plasma may also represent an opportunity to monitor somatic mutations in course of therapy.

Cell-free DNA and preoperative chemoradiotherapy for rectal cancer: a systematic review

BACKGROUND

Preoperative chemoradiotherapy is the standard of care for patients with locally advanced rectal cancer, yet valid circulating biomarkers are lacking. We aimed at systematically reviewing the literature of cell-free DNA and locally advanced rectal cancer.

METHODS

A systematic literature search was performed. We retrieved papers reporting a correlation between a clinical outcome and cell-free DNA for patients receiving chemoradiotherapy for locally advanced rectal cancer.

RESULTS

We included nine studies of a total of 615 patients. Only single-arm studies were identified, analyzing either the total level of cell-free DNA or tumor-specific DNA. Despite differences in the methodology and outcomes, eight of the nine studies showed a correlation between cell-free DNA and a clinical outcome.

CONCLUSIONS

Cell-free DNA might hold prognostic and predictive information for patients with locally advanced rectal cancer receiving preoperative chemoradiotherapy; although, firm conclusions are limited by the heterogeneity in this field.

Non-operative management of rectal cancer: understanding tumor biology

The management of locally-advanced rectal cancer involves a combination of chemotherapy, chemoradiation, and surgical resection to provide excellent local tumor control and overall survival. However, aspects of this multimodality approach are associated with significant morbidity and long-term sequelae. In addition, there is growing evidence that patients with a clinical complete response to chemotherapy and chemoradiation treatments may be safely offered initial non-operative management in a rigorous surveillance program. Weighed against the morbidity and significant sequelae of rectal resection, recognizing how to best optimize non-operative strategies without compromising oncologic outcomes is critical to our understanding and treatment of this disease.

Can an IL13 -1112 C/T (rs1800925) polymorphism predict responsiveness to neoadjuvant chemoradiotherapy and survival of Chinese Han patients with locally advanced rectal cancer?

We sought to determine whether a polymorphism in the Interleukin 13 gene (IL13), 1112 C/T (rs1800925) predicts responsiveness to neoadjuvant chemoradiotherapy (neoCRT) and prognosis in Chinese Han patients with locally advanced rectal cancer (LARC). Pre-treatment biopsies of primary rectal lesion and surgical specimens were collected from 58 patients with LARC, who were treated with neoCRT and surgery. Tumor DNA was extracted from these biopsies and sequenced to analyze the rs1800925 polymorphism. The tumor response to neoCRT was categorized using a tumor regression grade (TRG, 0-2 were poor responders; 3-4 were good responders). Analyses of progression free survival (PFS) and overall survival (OS) were carried out using the Kaplan-Meier method. Of the forty-six patients for whom tumor DNA was successfully sequenced, 23 were good responders to neoCRT (11 patients with a pathological complete response, i.e. pCR) and the other 23 were poor responders. Good and poor responders were equally likely to have a C/C genotype at rs1800925 (73.9%) as a T/T or C/T genotype (26.1%). There were no differences between the C/C and T/T+C/T genotypes with respect to the ypT0-2 ratio (38.2% vs. 41.7%, P = 1.0), ypN0 nodal status (67.6% vs. 50.0%, P= 0.314), 6-year PFS (67.6% vs. 50%, P=0.274), or 6-year OS (76.5% vs. 66.7%, P=0.441). Thus, the IL13-1112 C/T (rs1800925) polymorphism does not predict responsiveness to neoCRT or prognosis of Chinese Han patients with LARC.

Association of EGFR c.2073A>T Polymorphism with Decreased Risk of Diffusely Infiltrating Astrocytoma in a Brazilian Case-Control Study

Epidermal growth factor receptor (EGFR) gene overexpression has been implicated in the development of many types of tumors, including glioblastomas, the most frequent diffusely infiltrating astrocytomas. However, little is known about the influence of the polymorphisms of EGFR on EGFR production and/or activity, possibly modulating the susceptibility to astrocytomas. This study aimed to examine the association of two EGFR promoter polymorphisms (c-191C>A and c.-216G>T) and the c.2073A>T polymorphism located in exon 16 with susceptibility to astrocytomas, EGFR gene expression and survival in a case-control study of 193 astrocytoma patients and 200 cancer-free controls. We found that the variant TT genotype of the EGFR c.2073A>T polymorphism was associated with a significantly decreased risk of astrocytoma when compared with the AA genotype [sex- and age-adjusted odds ratio 0.51, 95% confidence interval 0.26–0.98]. No association of the two promoter EGFR polymorphisms (or combinations of these polymorphisms) and risk of astrocytomas, EGFR expression or survival was found. Our findings suggest that modulation of the EGFR c.2073A>T polymorphism could play a role in future therapeutic approaches to astrocytoma.

Germline and somatic genetic predictors of pathological response in neoadjuvant settings of rectal and esophageal cancers: systematic review and meta-analysis

Oncologists have pointed out an urgent need for biomarkers that can be useful for clinical application to predict the susceptibility of patients to preoperative therapy. This review collects, evaluates and combines data on the influence of reported somatic and germline genetic variations on histological tumor regression in neoadjuvant settings of rectal and esophageal cancers. Five hundred and twenty-seven articles were identified, 204 retrieved and 61 studies included. Among 24 and 14 genetic markers reported for rectal and esophageal cancers, respectively, significant associations in meta-analyses were demonstrated for the following markers. In rectal cancer, major response was more frequent in carriers of the TYMS genotype 2 R/2 R-2 R/3 R (rs34743033), MTHFR genotype 677C/C (rs1801133), wild-type TP53 and KRAS genes. In esophageal cancer, successful therapy appeared to correlate with wild-type TP53. These results may be useful for future research directions to translate reported data into practical clinical use.

Predictive and prognostic biomarkers for neoadjuvant chemoradiotherapy in locally advanced rectal cancer

Locally advanced rectal cancer is regularly treated with trimodality therapy consisting of neoadjuvant chemoradiation, surgery and adjuvant chemotherapy. There is a need for biomarkers to assess treatment response, and aid in stratification of patient risk to adapt and personalise components of the therapy. Currently, pathological stage and tumour regression grade are used to assess response. Experimental markers include proteins involved in cell proliferation, apoptosis, angiogenesis, the epithelial to mesenchymal transition and microsatellite instability. As yet, no single marker is sufficiently robust to have clinical utility. Microarrays that screen a tumour for multiple promising candidate markers, gene expression and microRNA profiling will likely have higher yield and it is expected that a combination or panel of markers would prove most useful. Moving forward, utilising serial samples of circulating tumour cells or circulating nucleic acids can potentially allow us to demonstrate tumour heterogeneity, document mutational changes and subsequently measure treatment response.

Prospective phase II trial of nimotuzumab in combination with radiotherapy and concurrent capecitabine in locally advanced rectal cancer

PURPOSE

The aim of the study was to evaluate the safety and efficacy of adding concurrent nimotuzumab to preoperative radiotherapy with concurrent capecitabine in locally advanced rectal cancer.

METHODS AND MATERIALS

Patients with rectal cancer (clinical stage T3/4 or N+) were scheduled to receive weekly nimotuzumab (400 mg; days -6, 1, 8, 15, 22, and 29). Capecitabine (825 mg/m(2)) was delivered orally twice daily for the duration of radiotherapy. Radiotherapy was administered at 50.4 Gy (45 + 5.4 Gy). The main endpoint was the pathologic complete response (pCR) rate.

RESULTS

Twenty-one patients with T3 or T4 disease were enrolled; 66.7 % were nodal-positive; the median distance from the anal verge was 5.5 cm. A pCR was achieved in four patients (19.0 %); 71.4 % patients obtained moderate or good tumor regression (Grade 2 and 3). Downstaging occurred in 15/21 (71.4 %) patients by T stage and 11/14 (78.6 %) by N stage. The actual dose intensities (median/mean, %) were nimotuzumab (100, 100) and capecitabine (100, 99.5). The most frequent Grade 1/2 toxicities were radiation dermatitis (57.1 %), nausea/vomiting (52.4 %), leukocytopenia (47.6 %), diarrhea (47.6 %), and proctitis (38.1 %). Grade 3 diarrhea was observed in 9.5 % of patients and Grade 3 leukocytopenia in 4.8 %.

CONCLUSION

These preliminary results indicate that nimotuzumab can be safely combined with radiotherapy plus concurrent capecitabine. The efficacy of this regimen (pCR = 19.0 %) was significantly higher than that observed in previous phase II trials of preoperative radiotherapy with concurrent capecitabine and cetuximab in rectal cancer. Further investigation of concurrent nimotuzumab with radiotherapy plus capecitabine is warranted.

EGF and EGFR genetic polymorphisms predict prognosis in locally advanced pharyngolaryngeal squamous cell carcinoma patients receiving postoperative concurrent chemoradiotherapy

Background

Epidermal growth factor (EGF) and its receptor (EGFR) are part of an important signaling pathway that is involved in the pathogenesis of squamous cell carcinoma of the head and neck (SCCHN). We hypothesized that EGF/EGFR genetic polymorphisms might have a prognostic impact on disease-free survival and overall survival (OS) in locally advanced SCCHN.

Materials and methods

The patient group included a consecutive cohort of 180 patients with locally advanced SCCHN who underwent postoperative concurrent chemoradiotherapy between 2002 and 2010. DNA from formalin-fixed, paraffin-embedded tumor tissues was genotyped for the single nucleotide polymorphism (SNP) of EGF A61G A>G, EGFR R521K G>A and G-216T. The log-rank test was applied to evaluate the impact of SNPs on the outcomes. Survival was estimated using the Kaplan–Meier statistical method.

Results

We demonstrated that EGF/EGFR SNPs might predict prognosis in patients with primary pharyngolaryngeal tumors, but not in those with oral cavity tumors. In pharyngolaryngeal tumor subgroup, EGF61 G/G genotype led to worse 5 year OS rate when compared to G/A or A/A genotypes (13.3% versus 34.3% versus 50.0%, P=0.017). The 5 year OS of patients with EGFR R521K G/G (11.1%) and G/A (15.9%) were lower than the A/A (62.5%) genotype (P=0.054). Patients carrying one or two unfavorable alleles had worse 5 year OS than those without unfavorable allele (not available versus 20% versus 71.4%, P=0.002). Multivariate analysis revealed that the highest risk of death was associated with the coexistence of two unfavorable genotypes (hazard ratio 25.7, 95% confidence interval =3.4–193.4; P=0.002).

Conclusion

In this study, we were able to demonstrate that the EGF A61G and EGFR R521K genetic polymorphisms might be important prognostic factors in patients with locally advanced primary pharyngolaryngeal squamous cell carcinoma who underwent postoperative concurrent chemoradiotherapy.

Prediction of response to preoperative chemoradiotherapy in patients with locally advanced rectal cancer

Preoperative chemoradiotherapy (CRT) combined with surgery has become a standard treatment strategy for patients with locally advanced rectal cancer (LARC). The pathological response is an important prognostic factor for LARC. The variety of tumor responses has increased the need to find a useful predictive model for the response to CRT to identify patients who will really benefit from this multimodal treatment. Magnetic resonance imaging (MRI), positron emission tomography-computed tomography (PET-CT), serum carcinoembryogenic antigen (CEA), molecular biomarkers analyzed by immunohistochemistry and gene expression profiling are the most used predictive models in LARC. The majority of predictors have yielded encouraging results, but there is still controversy. Diffusion-weighted MRI may be the best model to detect the dynamic changes of rectal cancer and predict the response at an early stage. Gene expression profiling and single nucleotide polymorphisms hold considerable promise to unveil the underlying complex genetics of response to CRT. Because each parameter has its own inherent shortcomings, combined models may be the future trend to predict the response.

Future directions in combined modality therapy for rectal cancer: reevaluating the role of total mesorectal excision after chemoradiotherapy

Most patients who develop rectal cancer present with locoregionally advanced (T3 or node-positive) disease. The standard management of locoregionally advanced rectal cancer is neoadjuvant concurrent chemoradiotherapy (nCRT), followed by radical resection (low-anterior resection or abdominoperineal resection with total mesorectal excision). Approximately 15% of patients can have a pathologic complete response (pCR) at the time of surgery, indicating that some patients can have no detectable residual disease after nCRT. The actual benefit of surgery in this group of patients is unclear. It is possible that omission of surgery in these patients, termed selective nonoperative management, can limit the toxicities associated with standard, multimodal combined modality therapy without compromising disease control. In this review, we discuss the clinical experiences to date using selective nonoperative management and various attempts at escalation of nCRT to improve the number of patients who have a pCR. We also explore several clinical, laboratory, imaging, histopathologic, and genetic biomarkers that have been tested as tools to predict which patients are most likely to have a pCR after nCRT.

Epidermal growth factor receptor expression as prognostic marker in patients with anal carcinoma treated with concurrent chemoradiation therapy

PURPOSE

To investigate the prognostic value of epidermal growth factor receptor (EGFR) expression in pretreatment tumor biopsy specimens of patients with anal cancer treated with concurrent 5-fluorouracil and mitomycin C-based chemoradiation therapy (CRT).

METHODS AND MATERIALS

Immunohistochemical staining for EGFR was performed in pretreatment biopsy specimens of 103 patients with anal carcinoma. EGFR expression was correlated with clinical and histopathologic characteristics and with clinical endpoints, including local failure-free survival (LFFS), colostomy-free survival (CFS), distant metastases-free survival (DMFS), cancer-specific survival (CSS), and overall survival (OS).

RESULTS

EGFR staining intensity was absent in 3%, weak in 23%, intermediate in 36% and intense in 38% of the patients. In univariate analysis, the level of EGFR staining was significantly correlated with CSS (absent/weak vs intermediate/intense expression: 5-year CSS, 70% vs 86%, P=.03). As a trend, this was also observed for DMFS (70% vs 86%, P=.06) and LFFS (70% vs 87%, P=.16). In multivariate analysis, N stage, tumor differentiation, and patients' sex were independent prognostic factors for CSS, whereas EGFR expression only reached borderline significance (hazard ratio 2.75; P=.08).

CONCLUSION

Our results suggest that elevated levels of pretreatment EGFR expression could be correlated with favorable clinical outcome in anal cancer patients treated with CRT. Further studies are warranted to elucidate how EGFR is involved in the response to CRT.

Polymorphisms in XPD and ERCC1 Associated with Colorectal Cancer Outcome

Using the comprehensive approach to selecting polymorphisms to date, we sought to examine whether recurrence in colorectal cancer was associated with inherited variation in three genes involved in DNA repair and cell proliferation. Three polymorphisms, which are excision repair cross-complementation 1 (ERCC1), xeroderma pigmentosum group D (XPD) and epidermal growth factor receptor (EGFR), were assessed in 257 postoperative stage II/III CRC patients with 5-fluorouracial chemotherapy in Taiwan. In addition, the correlations between genetic polymorphisms and patients’ clinicopathological features were investigated. Genotypes of XPD codon751 A/A and ERCC1 codon118 T/T were associated with regional recurrence in a statistically significant way (p = 0.018). Patients who carried XPD AA and ERCC1 TT genotypes demonstrated a significantly greater regional recurrence risk (OR = 5.625, 95% CI, 1.557–20.32). Inherited variation in XPD and ERCC1 was associated with outcome in patients with colorectal cancer in Taiwan. As the significant association of single-nucleotide polymorphisms has not been studied previously in colorectal cancer, these findings suggest novel sites of variation, in part explaining the range of treatment responses seen in this disease.

Prediction in rectal cancer

The treatment of rectal cancer largely depends on disease stage at diagnosis, based on which patients can be classified as low, intermediate, or high risk. Prognostic and predictive markers, specific to each risk category, can be applied for optimal risk classification and subsequent treatment allocation. These markers are either histopathological, determined with imaging, or have a biomolecular background. This review provides an overview of the current status of treatment options and the use of prognostic and predictive markers in each risk category. An effort was made to identify those markers that are currently lacking in, but have the potential to improve, the clinical decision process by discussing the data from recent studies aimed at the development of new prognostic and predictive markers. At this moment, none of the markers studied has been proven to be of significant, independent value, justifying implementation in daily clinical practice. However, recent developments in imaging techniques and biomolecular research do show great potential.

Response prediction in the multimodality therapy of locally advanced rectal cancer

SUMMARY Neoadjuvant therapies have been established in the multimodality treatment of locally advanced rectal cancer. Radiation with concurrent 5-fluorouracil-based chemotherapy followed by surgical resection is considered to be the standard of care in advanced rectal cancer. However, recent studies revealed that patients with complete histopathologic response seem to benefit most from neoadjuvant therapies. Consequently, predictive markers to allow individualization of multimodality therapy in locally advanced rectal cancer are mostly required to identify those who will benefit the most. Unfortunately, there is still an immense lack of factors for response assessment in patients with rectal cancer undergoing multimodality treatment. While conventional diagnostic tools lack sufficient accuracy to provide information for response assessment, newer techniques such as [18F]-fluorodeoxyglucose-PET and diffusion-weighted MRI show promising results. In addition, studies on molecular factors for response assessment in rectal cancer are encouraging but still do not provide a reliable instrument for utilization in clinical practice.

Neoadjuvant treatment in rectal cancer: actual status

Neoadjuvant (preoperative) concomitant chemoradiotherapy (CRT) has become a standard treatment of locally advanced rectal adenocarcinomas. The clinical stages II (cT3-4, N0, M0) and III (cT1-4, N+, M0) according to International Union Against Cancer (IUCC) are concerned. It can reduce tumor volume and subsequently lead to an increase in complete resections (R0 resections), shows less toxicity, and improves local control rate. The aim of this review is to summarize actual approaches, main problems, and discrepancies in the treatment of locally advanced rectal adenocarcinomas.

Identification of a biomarker profile associated with resistance to neoadjuvant chemoradiation therapy in rectal cancer

OBJECTIVE

To identify a biomarker profile associated with tumor response to chemoradiation (CRT) in locally advanced rectal cancer.

BACKGROUND

Rectal cancer response to neoadjuvant CRT is variable. Whereas some patients have a minimal response, others achieve a pathologic complete response (pCR) and have no viable cancer cells in their surgical specimens. Identifying biomarkers of response will help select patients more likely to benefit from CRT.

METHODS

This study includes 132 patients with locally advanced rectal cancer treated with neoadjuvant CRT followed by surgery. Tumor DNA from pretreatment tumor biopsies and control DNA from paired normal surgical specimens was screened for mutations and polymorphisms in 23 genes. Genetic biomarkers were correlated with tumor response to CRT (pCR vs non-pCR), and the association of single or combined biomarkers with tumor response was determined.

RESULTS

Thirty-three of 132 (25%) patients achieved a pCR and 99 (75%) patients had non-pCR. Three individual markers were associated with non-pCR; v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog mutation (P = 0.0145), cyclin D1 G870A (AA) polymorphism (P = 0.0138), and methylenetetrahydrofolate reductase (NAD(P)H) C677T (TT) polymorphism (P = 0.0120). Analysis of biomarker combinations revealed that none of the 27 patients with both tumor protein p53 (p53) and v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog mutations had a pCR. Further, in patients with both p53 and v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog mutations or the cyclin D1 G870A (AA) polymorphism or the methylenetetrahydrofolate reductase (NAD(P)H) C677T (TT) polymorphism (n = 52) the association with non-pCR was further strengthened; 51 of 52 (98%) of patients were non-pCR. These biomarker combinations had a validity of more than 70% and a positive predictive value of 97% to 100%, predicting that patients harboring these mutation/polymorphism profiles will not achieve a pCR.

CONCLUSIONS

A specific biomarker profile is strongly associated with non-pCR to CRT and could be used to select optimal oncologic therapy in rectal cancer patients. ClinicalTrials.org Identifier: NCT00335816.

Predictive factors of the response of rectal cancer to neoadjuvant radiochemotherapy

Locally advanced rectal cancer is currently treated with pre-operative radiochemotherapy (pRCT), but the response is not uniform. Identification of patients with higher likelihood of responding to pRCT is clinically relevant, as patients with resistant tumors could be spared exposure to radiation or DNA-damaging drugs that are associated with adverse side effects. To highlight predictive biomarkers of response to pRCT, a systematic search of PubMed was conducted with a combination of the following terms: "rectal", "predictive", "radiochemotherapy", "neoadjuvant", "response" and "biomarkers". Genetic polymorphisms in epithelial growth factor receptor (EGFR) and thymidylate synthase (TS) genes, the expression of several markers, such as EGFR, bcl-2/bax and cyclooxygenase (COX)-2, and circulating biomarkers, such as serum carcinoembryonic antigen (CEA) level, are promising as predictor markers, but need to be further evaluated. The majority of the studies did not support the predictive value of p53, while the values of Ki-67, TS and p21 is still controversial. Gene expression profiles of thousands of genes using microarrays, microRNA studies and the search for new circulating molecules, such as human telomerase reverse transcriptase mRNA and cell-free DNA, are providing interesting results that might lead to the identification of new useful biomarkers. Evaluation of biomarkers in larger, prospective trials are required to guide therapeutic strategies.

Prognostic value of serum soluble Fas in patients with locally advanced unresectable rectal cancer receiving concurrent chemoradiotherapy

OBJECTIVE

This study was designed to detect the changes of serum soluble Fas (sFas) levels in patients with locally advanced unresectable rectal cancer (LAURC), and to explore its prognostic value of response.

METHODS

Soluble samples were obtained from LAURC subjects, treated by concurrent chemoradiotherapy, before treatment and one month after treatment. Healthy donor serum samples were used as controls. sFas concentration was measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

The sFas levels before treatment and one month after treatment were both significantly higher in LAURC subjects than in healthy controls [(8.79±1.39) and (7.74±1.32) vs. (5.53±1.13) ng/L, P<0.01]. The sFas levels before treatment and one month after treatment were significantly lower in the response group (complete and partial responses) than in the non-response group (stable and progressive diseases) [(8.50±1.25) vs. (10.17±1.26) ng/L, P<0.01 and (7.50±1.24) vs. (8.90±1.13) ng/L, P<0.01, respectively]. The one-year survival rate was 54.2% and 82.6% in those with sFas levels >8.79 ng/L and <8.79 ng/L before treatment (P<0.02), respectively, 50.0% and 87.0% in those with sFas levels >7.74 ng/L and <7.74 ng/L one month after treatment (P<0.01), respectively.

CONCLUSIONS

The sFas level is higher in LAURC subjects than in healthy controls. Concurrent chemoradiotherapy can reduce sFas levels in LAURC patients. The monitoring of sFas may provide prognostic information for LAURC patients.

Prognostic role of EGFR gene copy number and KRAS mutation in patients with locally advanced rectal cancer treated with preoperative chemoradiotherapy

BACKGROUND

Epidermal growth factor receptor (EGFR), evaluated by immunohistochemistry, has been shown to have prognostic significance in patients with colorectal cancer. Gene copy number (GCN) of EGFR and KRAS status predict response and outcome in patients treated with anti-EGFR therapy, but their prognostic significance in colorectal cancer patients is still unclear.

METHODS

We have retrospectively reviewed the baseline EGFR GCN, KRAS status and clinical outcome of 146 locally advanced rectal cancer (LARC) patients treated with preoperative chemoradiotherapy. Pathological response evaluated by Dworak's tumour regression grade (TRG), disease-free survival (DFS) and overall survival (OS) were analysed.

RESULTS

Tumour regression grade 4 and TRG3-4 were achieved in 14.4 and 30.8% of the patients respectively. Twenty-nine (19.9%) and 33 patients (19.2%) had an EGFR/nuclei ratio >2.9 and CEP7 polisomy >50% respectively; 28 patients (19.2%) had a KRAS mutation. Neither EGFR GCN nor KRAS status was statistically correlated to TRG. 5-year DFS and OS were 63.3 and 71.5%, respectively, and no significant relation with EGFR GCN or KRAS status was found.

CONCLUSION

Our data show that EGFR GCN and KRAS status are not prognostic factors in LARC treated with preoperative chemoradiation.

XRCC1 gene polymorphism for prediction of response and prognosis in the multimodality therapy of patients with locally advanced rectal cancer

BACKGROUND

Neoadjuvant treatment strategies have been developed to improve survival of patients with locally advanced rectal cancer. Since mainly patients with major histopathologic response benefit from this therapy, predictive markers are needed. The gene polymorphism of the X-ray-repair-cross complementing (XRCC1-) gene (rs25487) was analyzed to predict response to neoadjuvant radiochemotherapy and prognosis in patients with locally advanced rectal cancer.

PATIENTS AND METHODS

81 patients (51 male; 30 female; median age 59 years) with locally advanced rectal cancer were included in this study. All patients received a neoadjuvant radiochemotherapy (50.4 Gy, 5-FU) followed by surgical therapy. Histomorphologic regression was defined as major response when resected specimens contained less than 10% viable tumor cells (n = 28) and minor response when more than 10% viable tumor cells (n = 53) were detected in the surgical specimen. Genomic DNA was extracted from paraffin-embedded tissues of all study patients. Allelic discrimination was performed by real-time polymerase chain reaction. Two allele-specific TaqMan probes in competition were used for amplification of the XRCC1 gene. Allelic genotyping was correlated with therapy response and prognosis.

RESULTS

Single-nucleotide polymorphism XRCC1 A399G (rs25487) was predictive for therapy response (P = 0.039). Within the AG genotype group, 17 (53%) patients showed a minor response and 15 (47%) patients a major response. In contrast, 39 (78%) of the patients with homogeneous AA or GG genotype were minor responders and only 11 (22%) major responders. No prognostic value was revealed for the XRCC1 A399G (rs25487) gene polymorphism in the multimodality therapy.

CONCLUSION

Our data supports the role of XRCC1 as a predictive marker for therapy response in the multimodality therapy of patients with locally advanced rectal cancer. Single-nucleotide polymorphism XRCC1 A399G (rs25487) could be applied to individualize treatment strategies.

The predictive value of genetic variations in the vascular endothelial growth factor A gene in metastatic colorectal cancer

Single-nucleotide polymorphisms (SNPs) in the vascular endothelial growth factor A (VEGF-A) gene may have clinical implications. The aim of this study was to investigate the possible predictive value of the VEGF-A SNPs, in patients with metastatic colorectal cancer (mCRC) treated with first-line capecitabine and oxaliplatin (XELOX). The study included 72 patients with mCRC. Genomic DNA was isolated from whole blood, and SNPs were analyzed by PCR. SNPs were correlated with response and progression-free survival (PFS). Haplotypes were estimated using the PHASE program. Response was observed in 21% of the patients with the -2578 CA genotype compared with 59% of the patients with CC+AA, P=0.002, in 26% of the patients with the -460 CT genotype compared with 57% with CC+TT, P=0.01, and in 27% of the patients with the +405 GC genotype compared with 54% with GG+CC, P=0.02. Two SNPs were significantly related to PFS. A haplotype with a significant relationship to response was identified. The results demonstrated obvious relationships between genetic variations in the VEGF-A gene and response to first-line XELOX in patients with mCRC, which translated to a significant difference in PFS. The results call for validation in a larger cohort of patients.

Epidermal growth factor (EGF) A61G polymorphism and EGF gene expression in normal colon tissue from patients with colorectal cancer

INTRODUCTION

EGF/EGFR interactions are important mechanisms behind colorectal tumour development and growth. Recently a single nucleotide polymorphism in the EGF gene has been identified (EGF A61G). It may be a potential predictor for survival of patients receiving EGFR-inhibitor cetuximab treatment, but the clinical importance and the functional influence on EGF gene expression levels in colorectal cancer (CRC) patients have not yet been further assessed. The aim of the present study was to investigate the relationship between EGF A61G genotype and EGF gene expression levels in colorectal adenocarcinomas and normal colon tissue.

MATERIAL AND METHODS

Eighty-one CRC patients were included in the study. Tissue samples from normal colon, adenocacinomas and corresponding blood samples were analysed by real-time PCR for EGF gene expression and EGF A61G genotype, respectively.

RESULTS

Thirty-three percent were AA, 48% and 19% A/G and G/G respectively. We found a significantly lower median age in the A/A group compared to the G/G group, suggesting a later time of diagnosis in the G/G patients. There was a significant difference between the median EGF gene expression among the three genotypes in normal colon (p < 0.001) but not in adenocarcinomas. Furthermore, the median EGF gene expression was lower in CRC tissue than in normal colon samples, (0.13 (range 0.01-6.4) vs. 0.76, (range 0.013-5.55)).

CONCLUSION

We suggest that EGF A61G genotype has a functional influence on EGF gene expression in normal colon in CRC patients. The clinical implications warrant further investigations in prospective trials.

Biomarkers for response to neoadjuvant chemoradiation for rectal cancer

Locally advanced rectal cancer (LARC) is currently treated with neoadjuvant chemoradiation. Although approximately 45% of patients respond to neoadjuvant therapy with T-level downstaging, there is no effective method of predicting which patients will respond. Molecular biomarkers have been investigated for their ability to predict outcome in LARC treated with neoadjuvant chemotherapy and radiation. A literature search using PubMed resulted in the initial assessment of 1,204 articles. Articles addressing the ability of a biomarker to predict outcome for LARC treated with neoadjuvant chemotherapy and radiation were included. Six biomarkers met the criteria for review: p53, epidermal growth factor receptor (EGFR), thymidylate synthase, Ki-67, p21, and bcl-2/bax. On the basis of composite data, p53 is unlikely to have utility as a predictor of response. Epidermal growth factor receptor has shown promise as a predictor when quantitatively evaluated in pretreatment biopsies or when EGFR polymorphisms are evaluated in germline DNA. Thymidylate synthase, when evaluated for polymorphisms in germline DNA, is promising as a predictive biomarker. Ki-67 and bcl-2 are not useful in predicting outcome. p21 needs to be further evaluated to determine its usefulness in predicting outcome. Bax requires more investigation to determine its usefulness. Epidermal growth factor receptor, thymidylate synthase, and p21 should be evaluated in larger prospective clinical trials for their ability to guide preoperative therapy choices in LARC.

Molecular targeted treatment and radiation therapy for rectal cancer

BACKGROUND

EGFR (epidermal growth factor receptor) and VEGF (vascular endothelial growth factor) inhibitors confer clinical benefit in metastatic colorectal cancer when combined with chemotherapy. An emerging strategy to improve outcomes in rectal cancer is to integrate biologically active, targeted agents as triple therapy into chemoradiation protocols.

MATERIAL AND METHODS

Cetuximab and bevacizumab have now been incorporated into phase I-II studies of preoperative chemoradiation therapy (CRT) for rectal cancer. The rationale of these combinations, early efficacy and toxicity data, and possible molecular predictors for tumor response are reviewed. Computerized bibliographic searches of Pubmed were supplemented with hand searches of reference lists and abstracts of ASCO and ASTRO meetings.

RESULTS

The combination of cetuximab and CRT can be safely applied without dose compromises of the respective treatment components. Disappointingly low rates of pathologic complete remission have been noted in several phase II studies. The K-ras mutation status and the gene copy number of EGFR may predict tumor response. The toxicity pattern (radiation-induced enteritis, perforations) and surgical complications (wound healing, fistula, bleeding) observed in at least some of the clinical studies with bevacizumab and CRT warrant further investigations.

CONCLUSION

Longer follow-up (and, finally, randomized trials) is needed to draw any firm conclusions with respect to local and distant failure rates, and toxicity associated with these novel treatment approaches.

EGFR pathway polymorphisms and bladder cancer susceptibility and prognosis

The epidermal growth factor receptor (EGFR) pathway has recently been appreciated as a central mediator of tumorigenesis and an important drug target; however, the influence of genetic variation in this pathway on bladder cancer is not understood. Pathway activation leads to cell proliferation, angiogenesis and is antiapoptotic. We sought to test the hypothesis that bladder cancer susceptibility and survival are modified by inherited variations in the sequence of the EGFR and its pathway members. We tested associations using a population-based study of 857 bladder cancer cases and 1191 controls from New Hampshire. Multifactor dimensionality reduction software was used to predict gene-gene interactions. We detected an increased risk of bladder cancer associated with variant genotypes for the single nucleotide polymorphisms EGFR_03 [adjusted odds ratio (OR) 1.7 (95% confidence interval (CI) 1.0-2.8)] and EGFR_05 [adjusted OR 1.5 (95% CI 1.0-2.1)] compared with wild-type. EGFR variants experienced longer survival than those with wild-type alleles [e.g. adjusted hazard ratio EGFR_1808 0.3 (95% CI 0.1-0.9)]. In contrast, the variant form of the ligand, EGF_04, had worse survival [adjusted hazard ratio 1.5 (95% CI 1.0-2.3)] compared with wild-type. Our findings suggest modified bladder cancer risk and survival associated with genetic variation in the EGFR pathway. Understanding these genetic influences on increased bladder cancer susceptibility and survival may help in cancer prevention, drug development and choice of therapeutic regimen.

Biologically conformal treatment: biomarkers and functional imaging in radiation oncology

'Conformal radiation therapy' is the standard of care in radiation oncology, referring to the process of shaping the radiation beam to precisely match a tumor's physical dimensions. We describe 'biologically conformal radiotherapy', in which the radiation oncologist matches the prescribed treatment to a tumor's biological characteristics and the host's predicted tolerance of radiation. This paradigm emphasizes that not all tumors are equally sensitive to radiation; conversely, some patients are especially susceptible to radiation's side effects. Patients bearing radioresistant tumors or those prone to toxicity may be best treated with the incorporation of targeted radiation modulators or, in extreme cases, by a different modality. The biological characteristics of tumors can be assessed by a wide range of techniques: functional imaging (positron emission tomography and advanced magnetic resonance imaging), single gene/protein molecular techniques and 'omic' technologies. This paper reviews the latest advances in the use of biomarkers and functional imaging in guiding patients to receive the most appropriate treatment.

Chemoradiotherapy and adjuvant chemotherapy for rectal cancer

Local recurrence is an important factor in determining the outcome of patients after surgery for rectal cancer, and various attempts have been made to reduce the local recurrence rate. Randomized controlled trials have shown that radiotherapy combined with total mesorectal excision can reduce the local recurrence rate in rectal cancer patients who undergo curative surgery. Chemoradiotherapy is more effective in achieving local control than radiotherapy alone, and preoperative chemoradiotherapy is superior to postoperative chemoradiotherapy in terms of adverse events. Recent advances have led to the identification of potential therapeutic targets such as epidermal growth factor receptor, vascular endothelial growth factor, and endothelial receptors. These new agents have been used in combination with conventional chemoradiotherapy, and higher pathological complete response rates have been reported for such combinations in comparison with conventional regimens. With regard to lateral node dissection, a recent study showed that postoperative chemoradiotherapy was more effective in reducing the local recurrence rate than lateral node dissection. As for adjuvant chemotherapy, one randomized controlled trial showed that patients who received uracil and tegafur as adjuvant therapy had significantly prolonged relapse-free survival times and overall survival times. As well, one metaanalysis has shown the efficacy of oral uracil-tegafur as adjuvant chemotherapy for rectal cancer.

Epidermal growth factor receptor R497K polymorphism is a favorable prognostic factor for patients with colorectal carcinoma

PURPOSE

It has been shown that the R497K polymorphism of the epidermal growth factor receptor (EGFR) has attenuated functions in ligand binding, tyrosine kinase activation, and growth stimulation. Because the activation of EGFR results in an unfavorable prognosis of patients with colorectal carcinoma, a pilot study was conducted to assess the influence of this polymorphism on colorectal carcinoma patients.

EXPERIMENTAL DESIGN

We retrospectively analyzed the effect of the R497K polymorphism of EGFR on clinicopathologic features in 209 colorectal carcinoma patients, including 100 with stage II/III colorectal carcinoma receiving curative surgery and the other 109 with metastatic diseases.

RESULTS

An excellent correlation in codon 497 statuses examined by patients' WBCs and tumor tissues was found but no significant between-group difference in patients with or without colorectal carcinoma (P = 0.97). A marked decrease on EGFR phosphorylation (P < 0.01) and c-Myc activation (P = 0.02) was observed in patients with R497K polymorphism, which is associated with decreased invasion (P = 0.01), lower nodal involvement (P = 0.02), reduced subsequent metastasis (P < 0.01), and longer disease-free (P < 0.01) as well as overall (P < 0.01) survival in stage II/III colorectal carcinoma patients who had received curative surgery. For patients with metastatic colorectal carcinoma, this polymorphism was associated with a higher response to 5-fluorouracil/oxaliplatin treatment (P = 0.02) and a longer survival (P < 0.01). By multivariate analysis, this polymorphism was also identified as an independent prognostic factor (P = 0.03).

CONCLUSIONS

These data suggest that the R497K polymorphism of the EGFR, by reducing its activation and a consequential down-regulation of its target genes, could be a key determinant for reduced tumor recurrence of stage II/III colorectal carcinoma patients receiving curative surgery and a longer survival of patients with stage II/III as well as metastatic colorectal carcinoma.

Phase I-II trial of cetuximab, capecitabine, oxaliplatin, and radiotherapy as preoperative treatment in rectal cancer

PURPOSE

To evaluate the safety and activity of preoperative radiotherapy (RT) with concurrent cetuximab, capecitabine, and oxaliplatin in rectal cancer patients.

PATIENTS AND METHODS

A total of 60 patients with rectal cancer (T3-T4 or N+, M1 allowed) entered the trial at five investigator sites; the data from 58 patients were assessable. Cetuximab was given as an initial dose of 400 mg/m2 7 days before the start of RT, and then at 250 mg/m2 once weekly during RT (50.4 Gy in 28 fractions). Capecitabine and oxaliplatin were administered according to an established schedule of oxaliplatin (50 mg/m2 on Days 1, 8, 22, and 29) and capecitabine (Days 1-14 and 22-35) at three dose levels: 1,000, 1,300, and 1,650 mg/m2/d during the Phase I part of the study. The main endpoint of the Phase II was the pathologic complete response rate.

RESULTS

Thirteen patients were included in the Phase I part of the study, and the maximal tolerated dose was not reached. Overall, 48 patients were treated at the recommended dose of capecitabine (1,650 mg/m2) and 45 patients (94%) underwent surgery. A pathologic complete response was observed in 4 patients (9%), and moderate (n=12), minimal (n=10), and no tumor regression (n=2) was noted in 24 (53%) of 45 patients. The mean radiation dose intensity, cetuximab, capecitabine, oxaliplatin was 98%, 95%, 94%, and 94%, respectively. The incidence of Grade 3-4 diarrhea was restricted to 19%. Postoperative complications of any grade occurred in 33% of patients.

CONCLUSIONS

The results of our study have shown that cetuximab can be combined safely with capecitabine and oxaliplatin plus RT. The low pathologic complete response rate achieved should stimulate additional preclinical investigations to establish the best sequence of triple combinations.

Germline polymorphisms may act as predictors of response to preoperative chemoradiation in locally advanced T3 rectal tumors

PURPOSE

Patients with locally advanced T3 rectal tumors who present with complete pathologic response to preoperative chemoradiation have a low rate of local recurrence and an excellent prognosis. Predictive markers for complete pathologic response are needed with the perspective of improving individualized treatment of these patients. This study was designed to investigate the predictive value of a new combination of three gene polymorphisms: thymidylate synthase, epidermal growth factor receptor Sp1-216, and epidermal growth factor A61G.

METHODS

Pretreatment blood samples from 60 patients with locally advanced T3 rectal tumors were analyzed for thymidylate synthase, epidermal growth factor receptor Sp1-216, and epidermal growth factor A61G gene polymorphisms by polymerase chain reaction. Treatment consisted of preoperative radiotherapy (total dose 65 Gy) and concomitant chemotherapy (Uftoral) followed by total mesorectal excision eight weeks after treatment. Pathologic response was evaluated according to the tumor regression grade system.

RESULTS

Thirty percent (18/60) of patients presented with complete pathologic response. Patients with thymidylate synthase genotype 2/2 had a significantly higher rate of complete pathologic response with 53 percent (8/15) compared with 22 percent in the 2/3 or 3/3 group. When combining thymidylate synthase and epidermal growth factor A61G genotype analysis, a small subgroup with a complete pathologic response rate of 100 percent was identified. Only a minor proportion of the complete responders were identified by this combination. Adding the epidermal growth factor receptor Sp1-216 genotype analysis, a complete pathologic response rate of 64 percent in the combination group was found compared with 21 percent and an 87 percent risk of being a noncomplete responder in the noncombination group.

CONCLUSIONS

A promising new combination of predictive markers for complete pathologic response was presented and warrants further investigation in prospective clinical trials.

Non-operative treatment after neoadjuvant chemoradiotherapy for rectal cancer

The past decade has seen pronounced changes in the treatment of locally advanced rectal cancer. Historically, the standard of care involved surgery followed by adjuvant radiotherapy or chemoradiotherapy. More recently, the emergence of neo-adjuvant chemoradiotherapy has fundamentally changed the management of patients with locally advanced disease. In clinical trials, pathological complete responses of up to 25% have raised the question as to whether surgery can be avoided in a select cohort of patients. A trial of omission of surgery for selected patients with complete response after preoperative chemoradiotherapy has shown favourable long-term results. In this article, we outline emerging factors for achieving pathological complete response, non-operative strategies to date, methods for prediction of response to chemoradiotherapy, and future directions with the addition of MRI as a radiological guide to complete response.

Adjuvant therapy for rectal cancer

Patients with stage II and III rectal cancer benefit from a multidisciplinary approach to treatment. Studies of postoperative adjuvant therapy consistently demonstrate decreases in locoregional recurrence with the use of radiation therapy. The use of postoperative chemotherapy results in improved disease-free survival and overall survival in certain studies. Preoperative radiation therapy decreases locoregional recurrence and in one study demonstrated an improvement in survival. The addition of chemotherapy to preoperative radiation results in improved locoregional control, but not survival. Preoperative chemoradiation is the standard of care for patients with clinical stage II and III rectal cancer in the United States due to improved local recurrence, acute and late toxicity, and sphincter preservation compared with postoperative chemoradiation. Promising approaches include the incorporation of new chemotherapeutic and biologic agents into chemoradiation and adjuvant chemotherapy regimens; new radiation techniques, such as the use of intraoperative radiation therapy and an accelerated concomitant radiation boost; and gene and protein expression profiling, to better predict response to treatment and prognosis.

Cyclin D1 Gene G870A Polymorphism Predicts Response to Neoadjuvant Radiotherapy and Prognosis in Rectal Cancer

PURPOSE

To investigate whether CCND1 genetic variations associated with a constitutive nuclear protein may influence either the pathologic response to preoperative RT or the prognosis in a series of rectal cancer patients.

METHODS AND MATERIALS

Seventy rectal cancer patients treated by neoadjuvant radiotherapy were included in the study. CCND1 exon 5 mutations were screened, and the G870A polymorphism was assessed for correlation with clinical variables, tumor response, and patient outcome.

RESULTS

No exon 5 mutation was found. Concerning the G870A polymorphism, the A/A variant was significantly associated with radiosensitivity (p = 0.022). Moreover, patients harboring the A allele were correlated with a lower risk of local failure (p = 0.017). Also, combination of the G870A polymorphism with the post-therapeutic lymph node status allowed the elaboration of a prognostic index, which accurately distinguished subgroups of patients with predictable recurrence-free (p = 0.003) and overall (p = 0.044) survival.

CONCLUSIONS

Although CCND1 exon 5 mutations are rare in rectal cancer, G870A polymorphism is a frequent variation that may predict radiosensitivity and prognosis.

Predictors of tumor response and downstaging in patients who receive preoperative chemoradiation for rectal cancer

BACKGROUND

The objective of this study was to identify predictive factors for pathologic complete response and tumor downstaging after preoperative chemoradiation for rectal cancer.

METHODS

Between 1989 and 2004, 562 patients with nonmetastatic rectal adenocarcinoma received preoperative chemoradiation and underwent mesorectal excision. The median radiation dose was 45 Gray (Gy) (range, 19.8-58.6 Gy), 77% of patients received concurrent infusional 5-fluorouracil, 20% of patients received concurrent capecitabine, and 3% of patients received other regimens.

RESULTS

Nineteen percent of patients achieved a pathologic complete response (CR), whereas 20% of patients had only microscopic residual disease at surgery, and 61% of patients had macroscopic residual disease at surgery. Downstaging of the tumor stage occurred in 57% of patients. The results from a univariate analysis indicated that tumor circumferential extent>60% (P=.033) and pretreatment carcinoembryonic antigen (CEA) level>2.5 ng/mL (P=.015) were associated significantly with lower pathologic CR rates. The univariate analysis also indicated that tumor circumferential extent>60% (P=.001), pretreatment CEA level>2.5 ng/mL (P=.006), and distance from the anal verge>5 cm (P=.035) were associated significantly with lower downstaging rates. The results from a multivariate logistic regression analysis indicated that greater circumferential extent of tumor (odds ratio [OR], 0.43; P=.033) independently predicted a lower pathologic CR rate. The multivariate logistic regression analysis also indicated that greater circumferential extent of tumor (OR, 0.49; P=.020) and greater distance from the anal verge (OR, 0.46; P=.010) independently predicted a lower downstaging rate.

CONCLUSIONS

Circumferential extent of tumor, CEA level, and distance from the anal verge predicted for the pathologic response to preoperative chemoradiation for patients with rectal cancer. Therefore, these factors may be used to predict outcomes for patients, to develop risk-adapted treatment strategies, and to target patients who participate in trials of newer therapies.

Prognostic and predictive value of baseline and posttreatment molecular marker expression in locally advanced rectal cancer treated with neoadjuvant chemoradiotherapy

PURPOSE

To evaluate expression of a panel of molecular markers, including p53, p21, MLH1, MSH2, MIB-1, thymidylate synthase, epidermal growth factor receptor (EGFR), and tissue vascular endothelial growth factor (VEGF), before and after treatment in patients treated with neoadjuvant chemoradiotherapy for locally advanced rectal cancer, to correlate the constitutive profile and dynamics of expression with pathologic response and outcome.

METHODS AND MATERIALS

Expression of biomarkers was evaluated by immunohistochemistry in tumor samples from 91 patients with clinical Stage II and III rectal cancer treated with preoperative pelvic radiotherapy (50 Gy) plus concurrent 5-fluorouracil by continuous intravenous infusion.

RESULTS

A pathologic complete remission was observed in 14 patients (15.4%). Patients with MLH1-positive tumors had a higher pathologic complete response rate (24.3% vs. 9.4%; p = 0.055). Low expression of constitutive p21, absence of EGFR expression after chemoradiotherapy, and high Dworak's tumor regression grade (TRG) were significantly associated with improved disease-free survival and overall survival. A high MIB-1 value after chemoradiotherapy was significantly associated with worse overall survival. Multivariate analysis confirmed the prognostic value of constitutive p21 expression as well as EGFR expression and MIB-1 value after chemoradiotherapy among patients not achieving TRG 3-4.

CONCLUSIONS

In our study, we observed the independent prognostic value of EGFR expression after chemoradiotherapy on disease-free survival. Moreover, our study suggests that a constitutive high p21 expression and a high MIB-1 value after neoadjuvant chemoradiotherapy treatment could predict worse outcome in locally advanced rectal cancer.

Magnifying endoscopic observation of the gastric mucosa, particularly in patients with atrophic gastritis

The gastric mucosal surface was observed using the magnifying fibergastroscope (FGS-ML), and the fine gastric mucosal patterns, which were even smaller than one unit of gastric area, were examined at a magnification of about 30. For simplicification, we classified these patterns by magnifying endoscopy in the following ways; FP, FIP, FSP, SP and MP, modifying Yoshii's classification under the dissecting microscope. The FIP, which was found to have round and long elliptical gastric pits, is a new addition to our endoscopic classification. The relationship between the FIP and the intermediate zone was evaluated by superficial and histological studies of surgical and biopsy specimens. The width of the band of FIP seems to be related to the severity of atrophic gastritis. Also, the transformation of FP to FIP was assessed by comparing specimens taken from the resected and residual parts of the stomach, respectively. Moreover, it appears that severe gastritis occurs in the gastric mucosa which shows a FIP. Therefore, we consider that the FIP indicates the position of the atrophic border.