Association of tumor-infiltrating lymphocytes with survival depends on primary tumor sidedness in stage III colon cancers (NCCTG N0147) [Alliance].

BACKGROUND: Tumor-infiltrating lymphocytes (TILs) are a robust and independent prognostic variable in localized colon cancer. Given reported differences in molecular features and prognosis of right- versus left-sided tumors, we examined the association of TIL densities with patient survival by primary tumor sidedness in stage III cancers, including clinical low- (T1-3, N1) and high-risk (T4 and/or N2) groups. PATIENTS AND METHODS: In a phase III trial of FOLFOX-based adjuvant chemotherapy, TIL densities were analyzed and dichotomized in colon carcinomas (N = 1532) based on a previously determined cut point optimized for disease-free survival (DFS). Right-sided tumors were defined as proximal to the splenic flexure. Associations of TILs and sidedness with 5-year DFS were examined using Kaplan-Meier methodology along with multivariable modeling and relative contribution analysis by Cox regression. RESULTS: Lower TIL densities were found in left- versus right-sided tumors (P < 0.0001). The association of TIL densities with DFS differed significantly by tumor sidedness (Pinteraction = 0.045). Overall, patient tumors with low (versus high) TILs had significantly poorer DFS in right-sided (hazard ratio 2.02, 95% confidence interval 1.45-2.82; Padj < 0.0001), but not left-sided tumors (Padj = 0.1731). Among clinical low-risk patients, low (versus high) TILs were adversely prognostic only in right-sided tumors (Padj = 0.0058). Among high-risk patients, low TILs were prognostic independent of sidedness (Padj < 0.025). The relative contribution of TILs to DFS was substantially greater in right- versus left-sided tumors (24% versus 1.5%). In high-risk tumors, TILs had the highest relative contribution to DFS (42%) of all variables. In low-risk tumors, the contribution of TILs (16%) to DFS was second to KRAS. CONCLUSIONS: The association of TIL densities with patient survival differed by primary tumor sidedness and clinical risk group, suggesting that TILs should be interpreted in this context among stage III colon cancers. GOV IDENTIFIER: NCT00079274; https://clinicaltrials.gov/ct2/show/NCT00079274.

Analysis of tumor microenvironmental features to refine prognosis by T, N risk group in patients with stage III colon cancer (NCCTG N0147) (Alliance).

BACKGROUND: Tumor-infiltrating lymphocytes (TILs), tumor budding, and micropapillary architecture may influence tumor growth and metastatic potential, thereby enhancing prognostic stratification. We analyzed these features and their relative contribution to overall outcome and in low (T1-3 N1) and high (T4 and/or N2) risk groups that are used to inform the duration of adjuvant chemotherapy in patients with resected stage III colon cancers. PATIENTS AND METHODS: Among 1532 patients treated in a phase III adjuvant trial of FOLFOX-based therapy, intraepithelial TIL densities, tumor budding, and micropapillary features were analyzed and quantified in routine histopathological sections with light microscopy. Optimal cut-points were determined in association with disease-free survival (DFS) in training and validation sets. Associations or relative contributions of individual features or combined variables with DFS were determined using multivariable Cox regression models. RESULTS: TILs, tumor budding, and micropapillary features were shown to differ significantly by T, N risk groups and by mismatch repair (MMR) status. Low TILs, high budding, and their combined variable [hazard ratio = 2.07 (95% CI, 1.50% to 2.88%); Padj < 0.0001], but not micropapillary features, were each significantly associated with poorer DFS in a training data set and confirmed in a validation set. TILs were prognostic in proficient mismatch repair (pMMR) and deficient mismatch repair (dMMR) tumors; budding was prognostic only in pMMR tumors. The percentage relative contribution of budding/TILs to DFS was second only to nodal status overall, was second (24.4%) after KRAS in low-risk patients, and was the most important contributor (45.4%) in high-risk patients. CONCLUSIONS: TIL density and tumor budding were each validated as significant prognostic variables and their combined variable provided robust prognostic stratification by T, N risk groups, being the strongest predictor of DFS among high-risk stage III patients. CLINICALTRIALS. GOV IDENTIFIER: NCT00079274.

Idiopathic myointimal hyperplasia is a distinct cause of chronic colon ischaemia.

AIM: Colon ischaemia (CI) is most commonly an acute and reversible manifestation of a transient, non-occlusive decrease of blood flow in the colonic microvasculature. Irreversible complications are uncommon and the progression to chronic CI remains controversial. Our objective was to identify cases of chronic CI and assess for distinct clinicopathological features. METHOD: A retrospective review was performed of CI patients having symptom chronicity of ≥ 1 month and ischaemic histology at our institution from 1994 to 2015. Demographic, clinical, endoscopic, radiological, pathological and outcome variables were abstracted. Histological evaluation was performed by two gastrointestinal pathologists. RESULTS: Fifteen patients (n = 9; 67% men) with a median age of 65 years (range 22-88) were identified. The most common presenting symptoms were diarrhoea and abdominal pain (n = 6, 86%; n = 5, 71%, respectively). The typical endoscopic appearance was segmental ulceration of the sigmoid colon (n = 6, 75%). Vascular imaging showed patent mesenteric vessels in all patients. Histopathological evaluation revealed venous intimal hyperplasia consistent with idiopathic myointimal hyperplasia of the mesenteric veins (IMHMV) in eight patients; the remainder showed non-specific ulceration and fibrosis. Surgical resection was performed in seven IMHMV patients, resulting in symptom resolution. On re-review of pre-resection biopsies, all IMHMV patients had characteristic changes of hyperplastic, thick-walled, hyalinized vessels in the lamina propria. CONCLUSIONS: IMHMV is a unique histopathological entity causing chronic CI. The small vessel histological changes in IMHMV are distinctive in colonic resections and undetectable by routine vascular imaging. Preoperative diagnosis of IMHMV is possible with endoscopic biopsy and segmental colon resection is curative.

Fluorescence in situ hybridization identifies high risk Barrett's patients likely to develop esophageal adenocarcinoma.

Barrett's esophagus (BE) with high-grade dysplasia (HGD) defines a group of individuals at high risk of progression to esophageal adenocarcinoma (EA). Fluorescence in situ hybridization (FISH) has been shown to be useful for the detection of dysplasia and EA in endoscopic brushing specimens from BE patients. The aim of this study was to determine whether FISH in combination with histological findings would further identify more rapid progressors to EA. This is a retrospective cohort study of high-risk patients, having a history of biopsy-confirmed HGD without EA, with an endoscopic brushing specimen analyzed by FISH while undergoing endoscopic surveillance and treatment between April 2003 and October 2010. Brushing specimens were assessed by FISH probes targeting 8q24 (MYC), 9p21 (CDKN2A), 17q12 (ERBB2), and 20q13 (ZNF217) and evaluated for the presence of polysomy, defined as multiple chromosomal gains (displaying ≥ 3 signals for ≥ 2 probes). Specimens containing ≥ 4 cells exhibiting polysomy were considered polysomic. HGD was confirmed by at least two experienced gastrointestinal pathologists. Of 245 patients in this study, 93 (38.0%) had a polysomic FISH result and 152 (62.0%) had a non-polysomic FISH result. Median follow-up was 3.6 years (interquartile range [IQR] 2-5 years). Patients with a polysomic FISH result had a significantly higher risk of developing EA within 2 years (14.2%) compared with patients with a non-polysomic FISH result (1.4%, P < 0.001). These findings suggest that a polysomic FISH result in BE patients with simultaneous HGD identifies patients at a higher risk for developing EA compared with those with non-polysomy.

Combining clinicopathological predictors and molecular biomarkers in the oncogenic K-RAS/Ki67/HIF-1α pathway to predict survival in resectable pancreatic cancer.

BACKGROUND: The dismal prognosis of patients diagnosed with pancreatic cancer points to our limited arsenal of effective anticancer therapies. Oncogenic K-RAS hyperactivation is virtually universal in pancreatic cancer, that confers drug resistance, drives aggressive tumorigenesis and rapid metastasis. Pancreatic tumours are often marked by hypovascularity, increased hypoxia and ineffective drug delivery. Thus, biomarker discovery and developing innovative means of countervailing oncogenic K-RAS activation are urgently needed. METHODS: Tumour specimens from 147 pancreatic cancer patients were analysed by immunohistochemical (IHC) staining and tissue microarray (TMA). Statistical correlations between selected biomarkers and clinicopathological predictors were examined to predict survival. RESULTS: We find that heightened hypoxia response predicts poor clinical outcome in resectable pancreatic cancer. SIAH is a tumour-specific biomarker. The combination of five biomarkers (EGFR, phospho-ERK, SIAH, Ki67 and HIF-1α) and four clinicopathological predictors (tumour size, pathological grade, margin and lymph node status) predict patient survival post surgery in pancreatic cancer. CONCLUSIONS: Combining five biomarkers in the K-RAS/Ki67/HIF-1α pathways with four clinicopathological predictors may assist to better predict survival in resectable pancreatic cancer.

Acute pancreas allograft rejection is associated with increased risk of graft failure in pancreas transplantation.

The effect of acute allograft rejection (AR) on long-term pancreas allograft function is unclear. We retrospectively studied 227 consecutive pancreas transplants performed at our institution between January 1, 998 and December 31, 2009 including: 56 simultaneous pancreas and kidney (SPK), 69 pancreas transplantation alone (PTA); and 102 pancreas after kidney (PAK) transplants. With a median follow-up of 6.1 (IQR 3-9) years, 57 patients developed 79 episodes of AR, and 19 experienced more than one episode. The cumulative incidence for AR was 14.7%, 19.7%, 26.6% and 29.1% at 1, 2, 5 and 10 years. PTA transplant (hazards ratio [HR]=2.28, p=0.001) and donor age (per 10 years) (HR=1.34, p=0.006) were associated with higher risk for AR. The first AR episode after 3 months post PT was associated with increased risk for complete loss (CL) (HR 3.79, p<0.001), and the first AR episode occurring during 3- to 12-month and 12- to 24-month periods after PT were associated with significantly increased risk for at least partial loss (PL) (HR 2.84, p=0.014; and HR 6.25, p<0.001, respectively). We conclude that AR is associated with increased risk for CL and at least PL. The time that the first AR is observed may influence subsequent graft failure.

Endoscopic ablative therapy for Barrett's esophagus: a potential cause of eosinophilic esophagitis.

Markedly increased esophageal eosinophils are associated with allergy- or reflux-based eosinophilic esophagitis. Other known disorders that cause this entity are unusual. To characterize the clinical, endoscopic, and histological findings of patients who develop marked esophageal eosinophilic infiltration after ablative therapy for Barrett's dysplasia. All patients who underwent endoscopic ablation of Barrett's esophagus between 1991 and 2009 with photodynamic therapy or radio frequency were screened for a pathologic descriptor of 'eosinophils' on biopsy. Patients whose biopsies demonstrated >15 eosinophils per high power (HPF) field in squamous epithelium after ablation were reviewed and included in the study group. Thirteen of 385 (3.4%) patients underwent ablation for Barrett's esophagus and subsequently had large numbers of intraepithelial eosinophils. All patients had long segment Barrett's (mean 8.0 cm) with low- or high-grade dysplasia or adenocarcinoma. All had undergone photodynamic therapy as their form of ablation. No patients had typical symptoms or endoscopic findings of eosinophilic esophagitis. Eleven patients were on proton pump inhibitors. The time between ablation and onset of esophageal eosinophilia ranged from 83 to 692 days. Intraepithelial eosinophil counts ranged from 30 to 150/HPF (mean 90). The majority of cases showed eosinophilic degranulation, spongiosis, increased papillary height, and basal zone thickening. The natural history of esophageal eosinophilia was variable after ablation, persisting consistently or sporadically on biopsy for up to 6 years. Ablation for Barrett's dysplasia can be followed rarely by eosinophil infiltrates with a histological resemblance to allergy-based eosinophilic esophagitis, but lacking dysphagia. The pathophysiology is unknown.

Endoscopic and surgical management of serrated colonic polyps.

BACKGROUND: Serrated polyps are an inhomogeneous group of lesions that harbour precursors of colorectal cancer. Current research has been directed at further defining the histopathological characteristics of these lesions, but definitive treatment recommendations are unclear. The aim was to review the current literature regarding classification, molecular genetics and natural history of these lesions in order to propose a treatment algorithm for surgeons to consider. METHODS: The PubMed database was searched using the following search terms: serrated polyp, serrated adenoma, hyperplastic polyp, hyperplastic polyposis, adenoma, endoscopy, surgery, guidelines. Papers published between 1980 and 2010 were selected. RESULTS: Sixty papers met the selection criteria. Most authors agree that recommendations regarding endoscopic or surgical management should be based on the polyp's neoplastic potential. Polyps greater than 5 mm should be biopsied to determine their histology so that intervention can be directed accurately. Narrow-band imaging or chromoendoscopy may facilitate the detection and assessment of extent of lesions. Complete endoscopic removal of sessile serrated adenomas in the left or right colon is recommended. Follow-up colonoscopy is recommended in 2-6 months if endoscopic removal is incomplete. If the lesion cannot be entirely removed endoscopically, segmental colectomy is strongly recommended owing to the malignant potential of these polyps. Left-sided lesions are more likely to be pedunculated, making them more amenable to successful endoscopic removal. CONCLUSION: Even though the neoplastic potential of certain subtypes of serrated polyp is heavily supported, further studies are needed to make definitive endoscopic and surgical recommendations.

Endoscopic diagnosis and resection of esophageal granular cell tumors.

Granular cell tumors (GCT) are uncommon neoplasms. There is controversy regarding the endoscopic diagnosis and treatment of esophageal GCT. We studied the endoscopic diagnosis and management of esophageal GCT among 23 patients identified in a single-institution pathology database. Medical records, pathology, and endoscopic images were reviewed. All patients underwent endoscopy and endoscopic ultrasonography (EUS), and endoscopic resection was performed in 10 patients. Seven of 23 patients had more than one esophageal GCT. Only six lesions exhibited a classic yellow discoloration. Among patients with a single GCT, three, four, and nine lesions were located in the proximal, middle, and distal esophagus, respectively. EUS showed hypoechoic, smooth-edged lesions usually confined to deep mucosa and submucosa. Standard forceps biopsy was diagnostic in 19 of 23 patients (83%). Ten GCT ≤ 10 mm in diameter underwent successful endoscopic mucosal resection without complication. The endoscopic appearance, location, and number of esophageal GCT are highly variable. Histological proof is still necessary for the differential diagnosis of this rare neoplasm. Endoscopic forceps biopsy is usually diagnostic. Endoscopic resection appears safe and effective in selected cases with lesions ≤ 10 mm.

Prognostic effect of activated EGFR expression in human colon carcinomas: comparison with EGFR status.

BACKGROUND: Evidence suggests that epidermal growth factor receptor (EGFR)-activation status may better predict the clinical behaviour of colon cancers than does EGFR expression. However, the prognostic effect of phospho-EGFR in primary colon cancer remains undefined. METHODS: Phospho-EGFR (Tyr-1173) and EGFR expression were analysed by immunohistochemistry (IHC) in tissue microarrays of TNM stage II and III colon cancers from completed adjuvant therapy trials (n=388). Staining intensity was scored and correlated with clinicopathological variables, DNA mismatch repair (MMR) status, rates of cell proliferation (Ki-67), apoptosis (caspase-3), and patient survival. RESULTS: Phospho-EGFR expression was detected in 157 of 388 (40%) tumours, whereas EGFR was found in 214 of 361 (59%). Although phospho-EGFR was unrelated to clinicopathological variables, strong EGFR intensity was associated with higher tumour stage (P=0.03). Tumours overexpressing EGFR (P=0.0002) or phospho-EGFR (P=0.015) showed increased Ki-67, but not caspase-3 expression. Phospho-EGFR was not prognostic. EGFR intensity was associated with worse disease-free survival (DFS) (hazard ratio (HR): 1.21 (1.03, 1.41); P=0.019) and overall survival (OS) (HR: 1.19 (1.02, 1.39); P=0.028). Tumours expressing both EGFR and phospho-EGFR had similar survival as EGFR alone. Stage and lymph node number were prognostic for DFS and OS, and histological grade for OS. EGFR was an independent predictor of DFS (P=0.042) after adjustment for stage, histological grade, age, and MMR status. CONCLUSION: Phospho-EGFR and EGFR expression were associated with tumour cell hyperproliferation. Phospho-EGFR was not prognostic, whereas increased EGFR intensity was independently associated with poor DFS.

MHC Class II alleles in ulcerative colitis-associated colorectal cancer.

OBJECTIVES: Patients with ulcerative colitis are at risk for colorectal cancer (CRC). Although prior studies have shown a link between HLA genotypes and ulcerative colitis (UC) susceptibility, none have investigated HLA genotypes and UC-CRC. We therefore investigated HLA-DR/DQ alleles in UC-CRC cases and UC-controls. Furthermore, since methylation of the Class II transactivator (CIITA) gene may silence HLA expression in tumours, we correlated HLA allele frequencies with CIITA gene methylation and HLA-DR expression. METHODS: Cases and controls were matched for duration/extent of ulcerative colitis, age, ethnicity and gender, but not for primary sclerosing cholangitis (PSC). DNA was extracted from archived tissue blocks from 114 UC-CRC cases and 114 UC-controls. HLA-DR/DQ genotyping was performed using sequence-specific-oligonucleotide polymerase chain reaction (SSO-PCR). CIITA methylation was determined using methylation-specific PCR. HLA-DR immunohistochemistry was done following standard protocols. RESULTS: UC-CRC cases were more likely than UC-controls to carry the DR17 or DR13 alleles (p<0.0001 or p = 0.02, respectively). Although CIITA methylation did not vary significantly between cases and controls, DR17 and DQ2 were associated with CIITA methylation (p = 0.04 and 0.02, respectively). UC-controls more frequently carried the DR7, DR1 or DQ5 alleles (p = 0.002, 0.05 or 0.01, respectively). After adjusting for PSC, DR17 remained significantly associated with an increased risk for UC-CRC while DR7 and DQ5 remained protective. CONCLUSIONS: We report a significant association between specific HLA alleles and either the risk for (DR17) or protection from (DR7, DQ5) UC-CRC. This suggests a possible genetic predisposition for increased UC-CRC risk. In addition, DQ2 and DR17 were associated with CIITA methylation.

Oesophageal lichen planus: the efficacy of topical steroid-based therapies.

BACKGROUND: Oesophageal lichen planus is an idiopathic inflammatory disorder characterized by significant oesophageal stricturing. Oesophageal lichen planus is a rare, difficult to diagnose, and likely an under recognized disease. As a result, there is no standardized approach to therapy and treatment strategies vary. AIM: To examine the utility of topical steroid therapy (fluticasone or budesonide) in the management of oesophageal lichen planus. METHODS: A retrospective chart review was conducted of patients diagnosed with oesophageal lichen planus who underwent baseline and follow up endoscopy pre and post topical steroid therapy between 1995 and 2016 at Mayo Clinic, Rochester MN. Average time between upper GI endoscopy was 3.2 months (0.7-11.7). Swallowed steroid preparations included fluticasone 880 µg twice daily or budesonide 3 mg twice daily. Patients were reviewed for symptomatic response to therapy using the Dakkak-Bennett dysphagia score (0-4, no dysphagia to total aphagia). Pre- and post-endoscopic findings were assessed. Additional baseline demographic, endoscopic, and histologic data were also obtained. RESULTS: We identified 40 patients who met the inclusion criteria. A significant reduction in median dysphagia score from 1 (0-4) to 0 (0-3) after steroid therapy (P < 0.001) was noted. 62% of patients reported resolution of their dysphagia after receiving topical corticosteroids. 72.5% had an endoscopic response to steroid therapy. CONCLUSION: Topical swallowed budesonide or fluticasone appear to effective treatment for oesophageal lichen planus.

Presence of intraepithelial food antigen in patients with active eosinophilic oesophagitis.

BACKGROUND: Although eosinophilic oesophagitis (EoE) is putatively mediated by an abnormal response to food antigen, the oesophagus is considered relatively impermeable to large molecules. AIM: To assess whether food antigens penetrate the oesophageal mucosa in patients with EoE. METHODS: Anti-gliadin staining was performed in three groups: active EoE, inactive EoE and EoE patients on a low or gluten free diet. To appraise the specificity of our results, we also performed gliadin staining on six patients without oesophageal disease who were consuming gluten. The groups with EoE on gluten also underwent endoscopic infusion with gluten containing soy sauce and repeat biopsies during the endoscopy. We measured eosinophil density, dilated intercellular spaces (on a 0-4+ scale) and gliadin in oesophageal mucosa by immunofluorescence. RESULTS: Patients with active EoE had significantly greater epithelial density of anti-gliadin staining when compared to inactive EoE (P < 0.0065) and gluten-free patients (P < 0.0008) at baseline and after soy infusion. Gliadin was not detected in non-EoE control patients. The distribution of gliadin was both cytoplasmic and nuclear. There was good correlation of dilated intercellular spaces grade and total gliadin staining intensity (r = 0.577, P = 0.0077). Acute oesophageal perfusion of a commercial gliadin-rich soy sauce did not lead to an increase in gliadin staining in active or inactive EoE. CONCLUSION: These findings suggest, although do not prove, that antigen penetration in active eosinophilic oesophagitis might be facilitated by impairment of epithelial integrity.

Flat adenomas in a colon cancer-prone kindred.

We describe new pathologic findings in a hereditary nonpolyposis colorectal cancer family. Affected family members developed multiple small adenomas with right-sided predominance; many adenomas had an unusual appearance featuring slightly elevated lesions with adenomatous changes confined to the upper regions of the colonic crypts. We have adopted the previously established term "flat adenoma" for these lesions. This phenotype may be a morphologic marker for at least one subset of hereditary nonpolyposis colorectal cancer.

Increased expression of the retinoblastoma gene in human colorectal carcinomas relative to normal colonic mucosa.

We report the first evidence of increased levels of the retinoblastoma (Rb) message in a majority of colorectal cancers when compared with normal mucosa. Southern blot analysis showed an increase in Rb gene copy number in at least 28% of colorectal carcinomas relative to normal mucosa. These results plus previous reports of nonrandom chromosome 13 gains in approximately 50% of colorectal cancers suggest that an increase in Rb gene copy number occurs frequently in these tumors. Possible mechanisms pertaining to overexpression of the Rb gene are discussed in relation to its role as a recessive cancer gene.

DNA damage-induced ephrin-B2 reverse signaling promotes chemoresistance and drives EMT in colorectal carcinoma harboring mutant p53.

Mutation in the TP53 gene positively correlates with increased incidence of chemoresistance in different cancers. In this study, we investigated the mechanism of chemoresistance and epithelial-to-mesenchymal transition (EMT) in colorectal cancer involving the gain-of-function (GOF) mutant p53/ephrin-B2 signaling axis. Bioinformatic analysis of the NCI-60 data set and subsequent hub prediction identified EFNB2 as a possible GOF mutant p53 target gene, responsible for chemoresistance. We show that the mutant p53-NF-Y complex transcriptionally upregulates EFNB2 expression in response to DNA damage. Moreover, the acetylated form of mutant p53 protein is recruited on the EFNB2 promoter and positively regulates its expression in conjunction with coactivator p300. In vitro cell line and in vivo nude mice data show that EFNB2 silencing restores chemosensitivity in mutant p53-harboring tumors. In addition, we observed high expression of EFNB2 in patients having neoadjuvant non-responder colorectal carcinoma compared with those having responder version of the disease. In the course of deciphering the drug resistance mechanism, we also show that ephrin-B2 reverse signaling induces ABCG2 expression after drug treatment that involves JNK-c-Jun signaling in mutant p53 cells. Moreover, 5-fluorouracil-induced ephrin-B2 reverse signaling promotes tumorigenesis through the Src-ERK pathway, and drives EMT via the Src-FAK pathway. We thus conclude that targeting ephrin-B2 might enhance the therapeutic potential of DNA-damaging chemotherapeutic agents in mutant p53-bearing human tumors.

Update on the differential diagnosis, surveillance and management of hereditary non-polyposis colorectal cancer.

Hereditary non-polyposis colorectal cancer (HNPCC) is the most common hereditary form of colorectal cancer (CRC), accounting for approximately 10% of the total CRC burden. HNPCC lacks premonitory physical stigmata, thereby making the family history crucial for diagnosis. Advances in molecular genetics during the past 2 years have led to the cloning of four HNPCC genes (MHS2, MLH1, PMS1 and PMS2). It is now possible to provide presymptomatic DNA testing followed by genetic counselling for gene carriers. Some studies have shown that adenomas in HNPCC are larger, more villous, and have more high grade dysplasia than sporadic cases, suggesting an accelerated adenoma-carcinoma sequence. Given the early age of onset and proximal predominance of CRC, we initiate colonoscopy at age 20-25 years and we recommend that it be performed every 1-2 years. The wealth of clinical and molecular genetic knowledge currently available to physicians about HNPCC can be used effectively for cancer control.