How Much Delay Matters? How Time to Treatment Impacts Overall Survival in Early Stage Lung Cancer.

OBJECTIVES: The aim of this study was to identify drivers of time from diagnosis to treatment (TTT) of surgically resected early stage non-small cell lung cancer (NSCLC) and determine the effect of TTT on post-resection survival. SUMMARY BACKGROUND DATA: Large database studies that lack relevant comorbidity data have identified longer TTT asa driver of worse overall survival. METHODS: From January 1, 2014 to April 1, 2018, 599 patients underwent lung resection for clinical stage I and II NSCLC. Random forest classification, regression, and survival were used to estimate likelihood of TTT = 0 (tissue diagnosis obtained at surgery), >0 (diagnosis obtained pre-resection), and effect of TTT on all-cause mortality. RESULTS: Patients with TTT > 0 (n = 413) had median TTT of 42 days (25-75 th percentile: 27-59 days). Patients with TTT = 0 (n = 186) had smaller tumors and higher percent predicted forced expiratory volume in 1 second (FEV 1 %). Patients with history of stroke, oncology consultation, invasive mediastinal staging, low and high extremes of FEV 1 % had longer TTT. Higher clinical stage, lack of preoperative stress test, anemia, older age, lower FEV1% and diffusion lung capacity, larger tumor size, and longer TTT were the most important predictors of all-cause mortality. One- and 5-year overall survival decreased when TTT was >50 days. CONCLUSIONS: Preoperative physiologic workup and multidisciplinary evaluation were the predominant drivers of longer TTT. Patients with TTT = 0have more favorable presentation and should be considered in TTT analyses for early stage lung cancer populations. The time needed to clinically stage and optimize patients for resection is not deleterious to overall survival until resection is performed after 50 days from diagnosis.

Adjuvant Therapy After Neoadjuvant Therapy for Esophageal Cancer: Who Needs It?

OBJECTIVE: We hypothesized that, on average, patients do not benefit from additional adjuvant therapy after neoadjuvant therapy for locally advanced esophageal cancer, although subsets of patients might. Therefore, we sought to identify profiles of patients predicted to receive the most survival benefit or greatest detriment from adding adjuvant therapy. BACKGROUND: Although neoadjuvant therapy has become the treatment of choice for locally advanced esophageal cancer, the value of adding adjuvant therapy is unknown. METHODS: From 1970 to 2014, 22,123 patients were treated for esophageal cancer at 33 centers on 6 continents (Worldwide Esophageal Cancer Collaboration), of whom 7731 with adenocarcinoma or squamous cell carcinoma received neoadjuvant therapy; 1348 received additional adjuvant therapy. Random forests for survival and virtual-twin analyses were performed for all-cause mortality. RESULTS: Patients received a small survival benefit from adjuvant therapy (3.2±10 months over the subsequent 10 years for adenocarcinoma, 1.8±11 for squamous cell carcinoma). Consistent benefit occurred in ypT3-4 patients without nodal involvement and those with ypN2-3 disease. The small subset of patients receiving most benefit had high nodal burden, ypT4, and positive margins. Patients with ypT1-2N0 cancers had either no benefit or a detriment in survival. CONCLUSIONS: Adjuvant therapy after neoadjuvant therapy has value primarily for patients with more advanced esophageal cancer. Because the benefit is often small, patients considering adjuvant therapy should be counseled on benefits versus morbidity. In addition, given that the overall benefit was meaningful in a small number of patients, emerging modalities such as immunotherapy may hold more promise in the adjuvant setting.

Markers of tumor inflammation as prognostic factors for overall survival in patients with advanced pancreatic cancer receiving first-line FOLFIRINOX chemotherapy.

BACKGROUND: Identifying pretreatment blood markers that distinguish prognostic groups of patients with advanced pancreatic ductal adenocarcinoma (PDAC) under first-line FOLFIRINOX chemotherapy has the potential to improve management of this condition. Aim of this study was to determine the prognostic utility of a range of pretreatment, inflammation-related, blood cell markers in this group of patients. MATERIAL AND METHODS: Data from a training cohort were analyzed to identify potential pretreatment blood markers correlating to survival outcomes. The most informative markers were further analyzed in a validation cohort comprised patients from a geographically separate cancer center undergoing the same treatment. RESULTS: A total of 138 consecutive patients receiving FOLFIRINOX chemotherapy between 2010 and 2019, constituted the training cohort. Neutrophil/lymphocyte (NLR), monocyte/lymphocyte (MLR), and platelet/lymphocyte ratio (PLR) as well as the systemic inflammatory response index (SIRI) and CA19.9 showed prognostic significance in addition to tumor stage. A pretreatment SIRI score cutoff of 2.35 differentiated between a poor prognostic group with median overall survival (mOS) 5.1 months and a better prognostic group, mOS 12.5 months. SIRI ≤/> 2.35 was predictive of mOS in patients with locally advanced and metastatic PDAC. SIRI was confirmed as a prognostic marker in a validation cohort of 67 patients with mOS of 13.4 months and 6.3 months for those with SIRI ≤ 2.35 and >2.35, respectively. Additional analysis revealed baseline SIRI as being prognostic within additional subgroups of patients in both cohorts. CONCLUSIONS: This large, retrospective, analysis of real-world patients receiving first-line FOLFIRINOX chemotherapy for advanced PDAC has identified the pretreatment blood SIRI as a strong prognostic marker for survival. This will allow better counseling of patients with regards to the benefits of treatment, improved stratification within clinical trials, and potentially identify groups of patients for novel therapy trials as first-line treatment.

Prospective cohort of cryobiopsy in interstitial lung diseases: a single center experience.

RATIONALE: Transbronchial cryobiopsy has been increasingly used to diagnose interstitial lung diseases. However, there is uncertainty regarding its accuracy and risks, mainly due to a paucity of prospective or randomized trials comparing cryobiopsy to surgical biopsy. OBJECTIVES: To evaluate the diagnostic yield and complications of cryobiopsy in patients selected by multidisciplinary discussion. METHODS: This was a prospective cohort from 2017 to 2019. We included consecutive patients with suspected interstitial lung diseases being considered for lung biopsy presented at our multidisciplinary meeting. MEASUREMENTS AND MAIN RESULTS: Of 112 patients, we recommended no biopsy in 31, transbronchial forceps biopsy in 16, cryobiopsy in 54 and surgical biopsy in 11. By the end of the study, 34 patients had had cryobiopsy and 24 patients, surgical biopsy. Overall pathologic and multidisciplinary diagnostic yield of cryobiopsy was 47.1% and 61.8%, respectively. The yield increased over time for both pathologic (year 1: 28.6%, year 2: 54.5%, year 3: 66.7%, p = 0.161) and multidisciplinary (year 1: 50%, year 2: 63.6%, year 3: 77.8%, p = 0.412) diagnosis. Overall rate of grade 4 bleeding after cryobiopsy was 11.8%. Cryobiopsy required less chest tube placement (11.8% vs 100%, p < 0.001) and less hospitalizations compared to surgical biopsy (26.5% vs 95.7%, p < 0.001), but hospitalized patients had a longer median hospital stay (2 days vs 1 day, p = 0.004). CONCLUSIONS: Diagnostic yield of cryobiopsy increased over time but the overall grade 4 bleeding rate was 11.8%.

Value of Lymphadenectomy in Patients Receiving Neoadjuvant Therapy for Esophageal Adenocarcinoma.

OBJECTIVE: The aim of this study was to assess the effect on survival of extent of lymphadenectomy during esophagectomy for patients undergoing multimodality (neoadjuvant) therapy for adenocarcinoma of the esophagus and esophagogastric junction using Worldwide Esophageal Cancer Collaboration data. SUMMARY BACKGROUND DATA: Previous worldwide data demonstrated that optimum lymphadenectomy during esophagectomy alone for esophageal cancer provides accurate staging and maximum survival. However, for patients undergoing neoadjuvant therapy for locally advanced adenocarcinoma, its value is unclear, leading to wide practice variability. METHODS: A total of 3859 patients with adenocarcinoma of the esophagus or esophagogastric junction received neoadjuvant therapy. The endpoint was all-cause mortality, reported as gain or loss of lifetime within 10 years. Lifetime predicted for each regional lymph node resected used quantile survival random forest methodology. RESULTS: Across all post-neoadjuvant ypTNM cancer categories, some degree of lymphadenectomy was associated with longer lifetime, but in a nonlinear fashion. For patients with ypN0 cancers, there was a modest gain in lifetime up to 25 lymph nodes resected and an incremental loss in lifetime as >25 were resected. For patients with ypN+ cancers, there was a robust gain in lifetime up to 30 lymph nodes resected and then an incremental loss in lifetime. CONCLUSIONS: Worldwide data for adenocarcinoma of the esophagus and esophagogastric junction demonstrate that lymphadenectomy during esophagectomy is a valuable component of neoadjuvant therapy. Survival is maximized when an optimum range of nodes is resected.

Repair, Reconstruct, or Divert: Fate of the Perforated Esophagus.

OBJECTIVES: The aim of this study was to determine differences in esophageal perforation populations undergoing different advanced interventions for perforated esophagus and identify predictors of treatment outcomes. SUMMARY BACKGROUND DATA: Contained esophageal perforation can often be managed expectantly, but uncontained perforation is uniformly fatal without invasive intervention. Treatment options for the latter range from simple endoscopic control through advanced intervention. Clinical presentation varies greatly and directs which intervention is most appropriate. METHODS: From 1996 to 2017, 335 patients were treated for esophageal perforation, and 166 for advanced interventions: 74 primary repair with tissue flap (repair), 26 esophagectomy and gastric pull-up (resection), and 66 esophagectomy and immediate diversion with planned delayed reconstruction (resection-diversion). Patient characteristics, clinical presentation, operative outcomes, and survival were abstracted. Pittsburgh Severity Scores (PSS) were retrospectively calculated. Random survival forest analysis was performed for 90-day mortality and competing risks for reconstruction after resection-diversion. RESULTS: Repair and resection patients had lower PSS than resection-diversion patients (3 vs 3 vs 6, respectively). Ninety-day mortality for repair, resection, and resection-diversion was 11% vs 7.7% vs 23%, and 5-year survival was 71% vs 63% vs 47%. Risk of death after resection-diversion was highest within 1 year, but 52% of patients had reconstruction of the upper alimentary tract within 2 years. CONCLUSIONS: Several advanced interventions exist for critically ill patients with uncontained esophageal perforation. Repair and organ preservation are always preferred; however, patients at extremes of illness might best be treated with resection-diversion, with the understanding that the competing risk of death may preclude eventual reconstruction.

Intercostal Blocks with Liposomal Bupivacaine in Thoracic Surgery: A Retrospective Cohort Study.

OBJECTIVE: Assess the efficacy of adding liposomal bupivacaine (LB) to bupivacaine-containing intercostal nerve blocks (ICNBs) to improve analgesia and decrease opioid consumption and hospital length of stay compared with bupivacaine-only ICNBs. DESIGN: This retrospective, observational investigation compared pain intensity scores and cumulative opioid consumption within the first 72 postoperative hours in patients who received ICNBs with bupivacaine plus LB (LB group) versus bupivacaine only (control group) after minimally invasive anatomic pulmonary resection. LB was tested for noninferiority on pain scores and opioid consumption. If LB was noninferior, superiority of LB was tested on both outcomes. SETTING: Academic tertiary care medical center. PARTICIPANTS: Adult patients undergoing minimally invasive anatomic pulmonary resection. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: For the secondary analysis, hospital length of stay was compared through the Cox regression model. Of 396 patients, 178 (45%) received LB and 218 (55%) did not. The mean (standard deviation) pain score was three (one) in the LB group and three (one) in the control group, with a difference of -0.10 (97.5% confidence interval [-0.39 to 0.18]; p = 0.41). The mean (standard deviation) cumulative opioid consumption (intravenous morphine equivalents) was 198 (208) mg in the LB group and 195 (162) mg in the control group. Treatment effect in opioid consumption was estimated at a ratio of geometric mean of 0.94 (97.5% confidence interval [0.74-1.20]; p = 0.56). Pain control and opioid consumption were noninferior with LB but not superior. Hospital discharge was not different between groups. CONCLUSIONS: LB with bupivacaine in ICNBs did not demonstrate superior postoperative analgesia or affect the rate of hospital discharge.

The "bowtie" reconstruction flap: A unique solution to cervical esophageal discontinuity repair.

OBJECTIVES: Describe a novel technique for repair of cervical esophageal discontinuity. STUDY DESIGN: A 66-year-old female underwent hiatal hernia repair with a Nissen fundoplication. This was complicated by ischemic necrosis of the proximal stomach requiring urgent return to the operative suite for partial gastrectomy, esophageal diversion and subsequent esophagectomy repaired with a colonic interposition graft by Thoracic Surgery. This was further complicated by a cervical esophageal colonic anastomotic leak maturing to a cervical esophageal fistula and necessitating jejunostomy tube placement and consultation to Head and Neck Surgery. METHODS: Case report. RESULTS: In a team approach with Otolaryngology and Thoracic Surgery, she underwent a unique, multilevel repair with a salivary bypass stent bridging the gap between the proximal esophagus and distal colonic conduit. Bilateral local advancement flaps were elevated using the skin lateral to the fistula on each side with a random blood supply pedicled medially. Each flap was rotated medially over the stent and imbricated at midline. Next, a left myogenous pectoralis flap was raised and rotated over the site of imbrication. Lastly, a split thickness skin graft from the thigh was harvested and sutured over the pectoralis flap. Three months postoperatively, the salivary bypass stent was removed and by five months, the fistula was completely closed. With cervical esophageal dilations bimonthly, the patient has graduated to an oral diet without need of her jejunostomy tube for nearly four months. CONCLUSION: This case report describes a novel and efficacious solution to cervical esophageal discontinuity.

Production of potent long-lasting consensus interferon using albumin fusion technology in Pichia pastoris expression system.

Consensus interferon (cIFN) is a wholly synthetic therapeutic protein which is used to treat hepatitis C/B and certain types of malignancies. It has short serum half-life, therefore, to maintain its therapeutic level in the human body it requires thrice-weekly administration. Various strategies like PEGylation and micro-encapsulation have been developed during the last few years to enhance the pharmacokinetics of small therapeutic peptides. This study executed the human albumin-fusion technology, a simple and flexible approach to extend the serum circulating half-life of cIFN, because human serum albumin (HSA) has long circulating half-life (19 days) and very minute immunological activities. We integrated the codon-optimized HSA-cIFN fusion gene into Pichia pastoris genome by homologous recombination. The selection of hyper-resistant P. pastoris clone against Zeocin™ achieved a high-level secretory expression (250 mg/L) of fusion protein. HSA-cIFN fusion protein was purified using one-step purification by affinity chromatography with 34% recovery. The SDS-PAGE and SEC-HPLC analysis confirmed the final purified product has molecular weight of 87 kDa with 98% purity. Western blot analysis using anti-IFN antibodies further verified the purified HSA-cIFN fusion protein. The specific biological activity was 2.1 × 106 IU/mg as assessed by cytopathic inhibition assay, and half-life of fusion protein was estimated by in vitro thermal and proteolytic stability studies. This work concludes that by using albumin fusion technology, codon optimization and one-step purification a high yield of 86 mg/L of biologically active protein with improved serum half-life was obtained.

Evaluating the ion exchange chromatography for matrix-assisted PEGylation and purification of consensus interferon.

Scientists have implemented protein-PEGylation technology for boosting-up the pharmacokinetics and stability of recombinant therapeutic proteins. In the present study, (a) matrix-assisted PEGylation was compared with solution-phase PEGylation and (b) matrix-assisted PEGylation was performed with different ion exchange resins for impact of chromatography medium on yield and purity of PEGylated product. DEAE Sepharose CL 6B, DEAE Fracto gel, and Macro cap Q ion exchange chromatography medium were compared for on column PEGylation and purification of cIFN. A MSC-PEG of 12.0 KDa was selected. cIFN was bound to ion exchange medium, and PEG solution was passed through resin for 180 Min, and protein was eluted by sodium chloride linear gradient. Yield and purity for mono-PEGylated cIFN with Macro cap Q matrix was 75% and 99%, respectively, whereas for DEAE Sepharose was 45% and 60%. DEAE Fracto gelTM purity was 85% with 50% yield of mono-PEGylated cIFN. Further investigation of in vitro biological activities demonstrated that about 30% antiviral activity was reduced as compared to unmodified cIFN. However, thermal stability was significantly improved. The present study proved that matrix-assisted PEGylation can improve the yield and purity of mono-PEGylated product, and Macro Cap resin provided the highest yield of a homogeneous product. In present study, (a) matrix-assisted PEGylation was compared with solution-phase PEGylation and (b) matrix-assisted PEGylation was performed with different ion exchange resins for impact of chromatography medium on yield and purity of PEGylated product. Matrix-assisted PEGylation increases the yield of mono-PEGylated product and further Macro CapTM produced highest yield and purity of PEGylated cIFN.

Retrobulbar metastasis of breast primary- Once in a blue moon lesion.

Breast cancer is the most common cancer in females and mostly metastasizes to liver, brain, bones, and lungs. It only rarely involves the choroid; signs of choroidal metastases become apparent late in the course of disease and are therefore linked to bad prognosis. These signs are often ignored as benign symptoms. Although many features may overlap with benign orbital diseases, MRI remains the modality of choice to help differentiate it from others. We present a case of a female patient who presented with visual impairment with unusual imaging features of retrobulbar choroidal metastases from primary breast cancer.

Correction to: Largely Unchanged Annual Incidence and Overall Survival of Pleural Mesothelioma in the USA.

The following disclaimer is missing from the original article.

Largely Unchanged Annual Incidence and Overall Survival of Pleural Mesothelioma in the USA.

BACKGROUND: Projections based on regulations curtailing asbestos use in the USA suggest that peak incidence of pleural mesothelioma would occur between 2000 and 2005 and then decline. We analyzed the National Cancer Database (NCDB) to assess current trends in disease incidence, patient demographics, cancer treatment, and survival. METHODS: The NCDB was queried to identify patients diagnosed with pleural mesothelioma from 2004 through 2014. Clinical and pathologic characteristics, treatments, and survival were analyzed. Risk factors for death were identified by multivariable Cox regression. RESULTS: A total of 20,988 patients with pleural mesothelioma were reported to the NCDB. The number of cases per year increased from 1783 to 1961, accounting for roughly 0.3% of all reported cancers each year. The proportion of elderly patients increased from 75 to 80%, but distribution by sex remained constant (20% female). The proportion of patients undergoing treatment increased from 34 to 54%. One-year survival increased from 37 to 47% and 3-year survival from 9 to 15% (p < 0.001). Factors associated with improved survival included younger age, female sex, epithelioid histology, treatment in an academic center, health insurance, higher income, and multimodality therapy. CONCLUSIONS: The annual incidence of mesothelioma has not declined this century and remains stable. Reporting of histologic and clinical staging has improved. National trends suggest that survival is slowly increasing despite an aging cohort. Multimodal therapy and treatment at academic centers are modifiable risk factors associated with improved survival.

Video-Assisted Thoracic Surgery Resection without Intraoperative Fluoroscopy after CT-Guided Microcoil Localization of Peripheral Pulmonary Nodules.

The aim of this brief report is to determine the safety and reliability of minimally invasive video-assisted thoracic surgery (VATS) resection without the aid of intraoperative fluoroscopy after computed tomography (CT)-guided microcoil localization of small peripheral pulmonary nodules. Twenty patients with peripheral lung nodules underwent percutaneous needle localization with a microcoil that was tagged back to the visceral pleural surface. Same-day VATS resection was performed without the use of intraoperative fluoroscopy. All 20 nodules were successfully localized in the CT procedure room, and all 20 nodules were resected with negative margins and no major complications.

Enhancing recombinant interleukin-6 production yield by fermentation optimization, two-step denaturing, and one-step purification.

Interleukin-6 a pleiotropic cytokine involved in a wide range of biological activities. So the large-scale production of biologically active recombinant human interleukin-6 is important for its structural and functional studies. Here, we report an optimized method for shake flask fermentation and a simplified high-yield purification procedure for the recombinant interleukin-6. This high-yield expression method not only involves the optimization of the fermentation condition but also the single step purification method as well as a two-step denaturing and one-step refolding process. This approach replaces the more conventional procedure of protein solubilization and refolding. Through applying these strategies, the final cell density and overall product yield of the recombinant human interleukin-6 were obtained as 20.4 g as cell biomass and 150 mg as purified active protein from the I-L of the culture. The purified protein was characterized by HPLC and SDS-PAGE. The results of the current work demonstrate that the described method may be used to develop the process for industrial-scale production of the biologically active recombinant interleukin-6 protein.

Evaluating the autoinduction expression system and one-step purification for high-level expression and purification of gallbladder-derived rhIL-1Ra.

Recent advancement in fermentation technologies resulted in the increased yields of recombinant proteins of biopharmaceutical and medicinal importance. Consequently, there is an important task to develop simple and easily scalable methods that can facilitate the production of high-quality recombinant protein. Most of the recent reports described the expression of recombinant human IL-1 receptor antagonist (rhIL-1Ra) in Escherichia coli using isopropyl-ß-d-thiogalacto pyranoside (IPTG), a nonmetabolizable and expensive compound, as an expression inducer. In this study, we describe the expression and one-step purification of gallbladder-derived rhIL-1Ra by autoinduction in E. coli. This method includes special media that automatically induce the target protein expression from T7 promoter and allow the production of the target protein in high yield than the conventional IPTG induction method. In addition to fermentation process improvements, one-step purification strategy is essential to make the process economical. We developed a single-step cation exchange chromatography and obtained 300 mg/L of rhIL-1Ra with 98% purity. Purified protein was characterized by SDS-PAGE and Ion exchange HPLC (IEX-HPLC). The described method can be used to scale up the production of rhIL-1Ra and other recombinant proteins.

Bioactivity studies of Huh-7 cells derived human epidermal growth factor expressed in Pichia pastoris.

Previously, we have reported cloning of human epidermal growth factor gene from Huh-7 cells and its extracellular expression in Pichia pastoris. The presented work is a detailed report regarding molecular characterization of Huh-7 cells-derived hEGF expressed in Pichia pastoris with special reference to its glycosylation profiling and bioactivity studies. Densitometric scanning of SDS-PAGE separated extracellular proteins from hEGF recombinant Pichia pastoris strain indicated that about 84% of the extracellular proteins were glycosylated. Size exclusion chromatography using Superdex 75 prep grade column was successfully utilized to separate fractions containing glycosylated and non-glycosylated extracellular proteins. In dot blot assay, hEGF was detected in both glycosylated and non-glycosylated fractions. Bioactivity assays revealed that both glycosylated and non-glycosylated fractions were bioactive as determined by cell viability assay. It was also observed that hEGF present in non-glycosylated fraction was relatively more bioactive than hEGF present in glycosylated fraction.

Simple procedure applying lactose induction and one-step purification for high-yield production of rhCIFN.

Recombinant consensus interferon (CIFN) is a therapeutic protein with molecular weight of 19.5 kDa having broad spectrum antiviral activity. Recombinant human CIFN (rhCIFN) has previously been expressed in Escherichia coli using isopropyl-ß-d-thiogalactopyranoside (IPTG), a non-metabolizable and expensive compound, as inducer. For economical and commercial-scale recombinant protein production, it is greatly needed to increase the product yield in a limited time frame to reduce the processing cost. To reduce the cost of production of rhCIFN in E. coli, induction was accomplished by using lactose instead of IPTG. Lactose induction (14 g/L) in shake flask experiment resulted in higher yield as compared with 1 mM IPTG. Finally, with single-step purification on DEAE sepharose, 150 mg/L of >98% pure rhCIFN was achieved. In the present study, an attempt was made to develop a low cost process for producing quality product with high purity. Methods devised may be helpful for pilot-scale production of recombinant proteins at low cost.

Optimization of conditions for high-level expression and purification of human recombinant consensus interferon (rh-cIFN) and its characterization.

Recombinant human consensus interferon (rh-cIFN) is an artificially engineered interferon (IFN) developed by recombining and reordering the protein sequences that exist in standard IFN. This recombination resulted into a drug that has the potential to work better than natural, standard IFN. In this study, we described optimized conditions for high-level expression and recovery of biologically active consensus IFN from inclusion bodies (IBs). A synthetic gene coding 166 amino acids of consensus IFN was cloned under the T7 promoter. Escherichia coli strain BL21DE3Plys was used to transform expression construct. For high-level expression, shake-flask fermentation conditions were standardized. For isolation of IBs, the sonication method was optimized. A variety of chaotropic agents including guanidine hydrochloride, urea, SDS, and detergents were studied for solubilization of IBs. For renaturation of solubilized denatured protein by the dilution process, parameters of dilution factor, temperature, and l-arginine were optimized. A one-step chromatography method was developed for high-yield purification of consensus IFN. rh-cIFN was characterized by SDS-PAGE, Western blot, and high-performance liquid chromatography. Purified protein has a molecular weight of 19.5 kDa and specific activity was 2.0 × 10(8) as determined by the cytopathic inhibition assay. This study concludes that by using optimized conditions, we obtained a yield of 100 mg/L of biologically active rh-cIFN, which is highest ever reported according to available data.