Biomarkers in cancer screening, research and detection: present and future: a review

Biomarkers provide a powerful and dynamic approach to understanding the spectrum of malignancies with applications in observational and analytic epidemiology, randomized clinical trials, screening, diagnosis and prognosis. Defined as alterations in the constituents of tissues or body fluids, these markers offer a means for homogeneous classification of a disease and risk factor, and they can extend one's basic information about the underlying pathogenesis of disease. The goals in cancer research include finding biomarkers that can be used for the early detection of cancers, design individual therapies, and to identify underlying processes involved in the disease. Because so many myriad processes are involved in the diseased states, the goal is similar to 'finding a needle in a haystack'. However, the development of many -omic technologies, such as genomics and proteomics, has allowed us to monitor a large number of key cellular pathways simultaneously. This has enabled the identification of biomarkers and signalling molecules associated with cell growth, cell death and cellular metabolism. These are also facilitating in monitoring the functional disturbance, molecular and cellular damage, and damage response. This brief review describes the development of biomarkers in cancer research and detection with emphasis on different proteomic tools for the identification and discovery of new biomarkers, different clinical assays to detect various biomarkers in different specimens, role of biomarkers in cancer screening and last but not the least, the challenges in this direction of cancer research.

Quality of life in newly diagnosed patients with lung cancer in a developing country: is it important?

There are no data regarding quality of life (QoL) assessments in lung cancer in developing countries like India. Quality of life was evaluated in 76 newly diagnosed lung cancer patients by using the World Health Organization Quality of Life questionnaire in Hindi (WHOQoL-Bref) (men 87%). The mean age was 55 years (SD = 10). Cough, dyspnoea, chest pain and haemoptysis were present in 83%, 72%, 66% and 43% of patients respectively. The median duration of symptoms was 5.9 months (range 1-13). Eighty-nine per cent had non-small cell lung cancer. The median pack-years smoked was 23 (range 0.5-88). Most patients (53%) had a Karnofsky's Performance Status (KPS) of 70 and 83% had stage III or IV disease. Quality of life did not correlate with age, gender, presence or duration of symptoms, histological type, stage of disease or degree of smoking. The physical and psychological domains of QoL correlated significantly with the KPS (P = 0.001 and P = 0.01 respectively). Patients with a KPS of 80 had better physical (P < 0.001), psychological (P < 0.01) and social (P < 0.05) QoL than those with a KPS of 70. In conclusion, patients with lung cancer in a developing country like India have an unsatisfactory QoL. The Karnofsky's Performance Scale is a simple and reliable surrogate marker for assessing QoL in these patients. Larger multi-centric studies may help in providing a more comprehensive evaluation of the effect of various demographic and clinical variables on QoL in this setting.

Effect of antioxidants on STAT3, cell survival gene products, apoptosis and chemoresistance in lung cancer cells

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Background: We had earlier demonstrated that antioxidants (beta carotene, vitamins C and E) enhance the apoptotic effect of paclitaxel and carboplatin in vitro and there was a suggestion that when used as an adjunct to the above chemotherapeutic agents in patients with NSCLC, they might enhance the efficacy of the latter. To elucidate the mechanism underlying the synergistic effect between antioxidants and chemotherapy, in the present study we evaluated the effect of antioxidants on STAT3 activation in NSCLC cells. Since this transcription factor has been shown to regulate multiple oncogenic pathways, including pathways regulating tumor cell survival, we further studied how STAT3 modulation relates to apoptosis and downstream apoptosis regulatory proteins. Methods: H520 cells were treated with antioxidants. STAT3 proteins were assessed by western blotting and their nuclear localization was evaluated by immunocytochemistry. Antiapoptotic proteins (survivin, Bcl-2, Bcl-xl and cyclin D1) were evaluated by Western blotting. To assess the interaction, cells were treated with chemotherapy (Paclitaxel and Carboplatin) with or without antioxidants and the effect was assessed by Live & Dead assay, MTT assay and flowcytometry. Results: Antioxidants inhibited STAT3 phosphorylation in a dose and time dependent manner before the initiation of cell death and depleted the nuclear pool of STAT3. This effect was specific since there was no effect on STAT5 phosphorylation and was reversible since STAT 3 reverted back to its constitutively activated state after the removal of antioxidants. Antioxidants suppressed the expression of antiapoptotic proteins Bcl -2, Bcl-xl, cyclin D1 and survivin. This resulted in the inhibition of proliferation of cells and induction of apoptosis as evident on caspase 3 activation and PARP cleavage. Antioxidants arrested the cells in G0/G1 phase of cell cycle making them more vulnerable to the cytotoxic effects of chemotherapy. This synergy was evident on live and dead assay. Conclusions: Our results demonstrate that antioxidants are potent inhibitors of STAT3 phosphorylation and can have a potential role as an adjunct to chemotherapy in lung cancer.

No significant financial relationships to disclose.

Cardiac sarcoidosis: an uncommon presentation of sarcoidosis in India

Cardiac involvement in sarcoidosis is uncommon. The manifestations of cardiac sarcoidosis are protean and vary from benign ectopics to life threatening ventricular tachycardias. High index of suspcion and early aggressive intervention is required for the diagnosis and treatment of this condition. Early diagnosis is essential since ventricular tachycardia is the most common terminal event in these patients if left untreated. Corticosteroids are needed early in these patients which along with other antiarrhythmic management strategies including intracardiac defibrillator form the backbone of treatment. We describe four patients who were diagnosed to have pulmonary and cardiac sarcoidosis. Their varied presentations highlight the difficulties that may occur in the diagnosis. Furthermore, the need for proper management is stressed, as a delay in diagnosis may be fatal.

Predictors of development and outcome in patients with acute respiratory distress syndrome due to tuberculosis

OBJECTIVE

To study the predictors of development and determinants of outcome in patients with acute respiratory distress syndrome (ARDS) due to tuberculosis (TB).

METHODS

Retrospective case-control study of demographic, clinical and laboratory data of hospitalised adult patients with active TB.

RESULTS

Of 2733 TB patients treated during 1980-2003, 29 (1.06%; 1.21 patients/year; mean age 31.6 +/- 10.9 years; 16 males) developed ARDS (cases). Seven had pulmonary TB and 22 had miliary TB (MTB); 298 (mean age 32.0 +/- 14.2 years; 110 males) who did not develop ARDS constituted controls. Presence of MTB (OR 4.6, 95%CI 1.2-17.8; P = 0.02), duration of illness beyond 30 days at presentation (OR 177.9, 95%CI 39-811.7; P < 0.001), absolute lymphocyte count < 1625/ mm3 (OR 4.5, 95%CI 1.1-19.3; P = 0.04) and serum ALT > 100 IU (OR 15.7, 95%CI 3.0-81.1, P < 0.001) were independent predictors of ARDS development. Twelve cases died (41.4%). Patients with APACHE II score >18; those with APACHE II score <18 in the presence of hyponatraemia and PaO2/FIO2 ratio <108.5 were likely to die.

CONCLUSIONS

In patients with TB, prolonged illness, MTB, absolute lymphocytopaenia and elevated ALT are independently associated with ARDS development. APACHE II score, serum sodium and PaO2/FIO2 ratio are determinants of outcome.

Stem cell markers: ABCG2 and MCM2 expression in retinoblastoma

BACKGROUND/AIM

The authors studied the expression of cancer stem cell surface marker, ABCG2, and neural stem cell marker, MCM2, in retinoblastoma and correlated clinicopathologically.

METHODS

Among 39 retinoblastomas, 18 tumours were not subjected to preoperative/postoperative chemotherapy, 15 tumours underwent postoperative chemotherapy, and six tumours had preoperative chemotherapy. There were 20 tumours with no invasion and 19 tumours with invasion of choroid/optic nerve. ABCG2 and MCM2 expression was studied by immunohistochemistry.

RESULTS

ABCG2 was positive in six of six and MCM2 was positive in five of six tumours that had recurred in the orbit or metastasised. ABCG2 was positive in 15/19 tumours with invasion. MCM2 was positive in 16/19 tumours with invasion. Invasive tumours showed higher expression of ABCG2 (p < 0.01) and MCM2 (p < 0.01) proteins. There was no correlation with differentiation and laterality of the tumours. Non-neoplastic retina was positive for ABCG2 and MCM2.

CONCLUSION

ABCG2 and MCM2 were expressed more in invasive tumours. Further studies are needed to understand the significance of ABCG2 and MCM2 expression in retinoblastoma.

Survival in small cell lung cancer in India: Prognostic utility of clinical features, laboratory parameters and response to treatment

BACKGROUND

Predictors of survival and response to treatment in patients with small cell lung cancer (SCLC) are ill-defined and unclear. In an attempt to assess the impact of common presenting symptoms and laboratory values on survival, we undertook this retrospective review of patients with SCLC. To our knowledge, there is no study on survival in SCLC patients from the Indian subcontinent.

DESIGN

Retrospective Cohort study.

MATERIALS AND METHODS

All newly diagnosed small cell lung cancer cases from December 2001 through December 2004, were identified and clinical data on presenting symptoms and laboratory findings from their hospital records, noted. The influence of various pretreatment factors on survival was investigated using Kaplan-Meier plots and Cox multivariate regression model.

RESULTS

76 subjects were included (84% males, 91% smokers). 57% patients had five or more symptoms at presentation. Cumulative symptom burden was strongly associated with survival (P =0.02). Survival was also significantly related with Karnofsky performance status (KPS) (P =0.04), disease extent (P =0.03) and symptomatic response to treatment (P< 0.001). Patients with higher hemoglobin (P =0.02), serum sodium (P =0.04) and serum globulin (P =0.02), survived significantly longer. By multivariate regression analysis, hemoglobin, KPS and brain metastases, were significant predictors of survival (P =0.01, P =0.02, P< 0.01 respectively).

CONCLUSION

Cumulative symptom burden, KPS, disease extent and symptomatic assessment of improvement after treatment, are useful predictors of survival. This has important clinical implications, keeping in view, the infrastructure and cost involved in more objective tests like CT scan, for evaluation of disease extent and prognosis. These findings can provide a simple basis for predicting prognosis in small cell lung cancer, especially in developing countries like ours.

A stepped approach for prediction of obstructive sleep apnea in overtly asymptomatic obese subjects: a hospital based study

BACKGROUND AND PURPOSE

Prevalence of obstructive sleep apnea (OSA) is high in obese subjects, many of whom may not be overtly symptomatic. Polysomnography (PSG) is a costly and time-consuming investigation. Since it is not feasible to subject all obese individuals to PSG, it is useful to define predictors of OSA among these subjects.

PATIENTS AND METHODS

One hundred and eighteen obese subjects [body mass index (BMI)> or =25 kg/m(2)] presenting to the hospital with non-sleep related complaints were included, of which 53 subjects with PSG evidence of OSA [apnea-hypopnea index (AHI)> or =15/h] were defined as cases and 65 subjects without any evidence of OSA (AHI<15/h) were defined as controls. Anthropometry, biochemical investigations, blood gas analysis, pulmonary function tests, and PSG were performed for all subjects.

RESULTS

Waist hip ratio (WHR) (as percentage of a standard) [odds ratio (95% CI): 1.07 (1.00-1.14); P = 0.049] male gender [odds ratio (95% CI): 3.97 (0.99-15.81); P = 0.046] and neck circumference (NC) [odds ratio (95% CI): 1.23 (1.03-1.47); P = 0.023] were found to be independent predictors of OSA. Overnight oxygen desaturation data were evaluated in patients selected as having OSA on the basis of these clinical markers, and the best cut-off for level of desaturation (10%) was defined. The stepped approach had a specificity, sensitivity, positive and negative predictive value of 89.2, 88.5, 86.8 and 90.6%, respectively, for the diagnosis of OSA.

CONCLUSIONS

Male gender, WHR and NC are independent predictors of OSA in overtly asymptomatic obese subjects. A stepped approach to diagnose OSA should be used, as it is accurate and cost-effective.

Unilateral pulmonary agenesis: an uncommon cause of lower zone lung opacity

Congenital abnormalities of the lung are rare and are often misdiagnosed. We report the case of a young girl who was initially diagnosed to have pleural effusion with collapse. After detailed evaluation including computerised tomographic (CT) scan and fiberoptic bronchoscopy, a final diagnosis of unilateral pulmonary agenesis was made. This condition must be suspected in differential diagnosis in a young person presenting with features of lung collapse.

Clinical and echocardiographic findings in patients with myocardial toxicity due to scorpion sting

BACKGROUND

Myocardial toxicity following a sting by the Indian red scorpion (Mesobuthus tamulus) is a life-threatening medical emergency. A perusal of the published literature suggests that this problem has seldom been studied systematically.

METHODS

We retrospectively studied the clinical presentation and echocardiographic findings in 24 patients (mean [SD] age 23.2 [11.7] years; 19 males) with myocardial toxicity caused by the sting of an Indian red scorpion (Mesobuthus tamulus). They were treated with inotropic support and diuretics depending on the requirement. At admission, oral L-carnitine was administered in a dose of 1980 mg/day in three divided doses till the left ventricular (LV) function normalized. None of the patients received digitalis, prazosin, hydrocortisone or antivenin.

RESULTS

Extreme anxiety and severe pain at the site of sting were present in all the patients. Hypotension (n = 19), pulmonary oedema (n= 15) and acute renal failure (n=8) were the other presenting features. Chest X-ray revealed cardiomegaly in 8 and pulmonary oedema in 13 patients. Serum creatinine phosphokinase levels were elevated more than two times the upper limit of normal (200 IU/L) in 22 patients (92%). The mean duration of hospitalization was 5 days (range 3- 11 days). L-carnitine treatment resulted in significant reduction in the LV diameter (mm) in diastole (47.6 [6.2] v. 42 [6.1], p < 0.01) and systole (42 [7.1] v. 28.2 [4], p<0.001); end-diastolic volume (ml) (108.7 [31.9] v. 81 [26.7], p <0.01) and end-systolic volume (ml) (81.3 [30.9] v. 31.1 [10.7], p < 0.001); and significant improvement in the stroke volume (ml) 27.8 [13.2] v. 61.7 [6.2], p<0.001) and ejection fraction (%) (25.5 [12.8] v. 61.2 [6.5], p<0.001). All the patients responded well to treatment and none died.

CONCLUSION

Our initial observations suggest a potential benefit with additional oral L-carnitine treatment in patients with myocardial toxicity caused by scorpion sting presenting with hypotension and severe LV dysfunction. These findings merit further study.

Laser bronchoscopy--current status

The majority of patients with lung cancer have advanced disease with severe endobronchial symptoms such as cough, dyspnea, and hemoptysis for which palliation is required. Laser resection of endobronchial lesions located in the trachea, mainstem or proximal lower lobe bronchi provides significant and rapid improvement in the patient's symptoms. Neodymium:yttrium-aluminium-garnet (Nd:YAG) laser is gaining popularity due to efficient photocoagulation, good penetration and excellent hemostasis. Complications are rare and can be minimized by following standardized techniques and safety guidelines. Laser resection is equally effective with the rigid and flexible bronchoscope. The future may see combinations of laser with other palliative modalities to improve the chances of a symptom-free life for lung cancer patients.

Multidrug-resistant tuberculosis

Multidrug-resistant tuberculosis (MDR-TB) caused by Mycobacterium tuberculosis resistant to both isoniazid and rifampicin with or without resistance to other drugs is among the most worrisome elements of the pandemic of antibiotic resistance. Globally, about three per cent of all newly diagnosed patients have MDR-TB. The proportion is higher in patients who have previously received antituberculosis treatment reflecting the failure of programmes designed to ensure complete cure of patients with tuberculosis. While host genetic factors may probably contribute, incomplete and inadequate treatment is the most important factor leading to the development of MDR-TB. The definitive diagnosis of MDR-TB is difficult in resource poor low income countries because of non-availability of reliable laboratory facilities. Efficiently run tuberculosis control programmes based on directly observed treatment, short-course (DOTS) policy is essential for preventing the emergence of MDR-TB. Management of MDR-TB is a challenge which should be undertaken by experienced clinicians at centres equipped with reliable laboratory service for mycobacterial culture and in vitro sensitivity testing as it requires prolonged use of expensive second-line drugs with a significant potential for toxicity. Judicious use of drugs, supervised individualised treatment, focussed clinical, radiological and bacteriological follow up, use of surgery at the appropriate juncture are key factors in the successful management of these patients. In certain areas, currently available programme approach may not be adequate and innovative approaches such as DOTS-plus may have to be employed to effectively control MDR-TB.

Extrapulmonary tuberculosis

Extrapulmonary involvement can occur in isolation or along with a pulmonary focus as in the case of patients with disseminated tuberculosis (TB). The recent human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS) pandemic has resulted in changing epidemiology and has once again brought extrapulmonary tuberculosis (EPTB) into focus. EPTB constitutes about 15 to 20 per cent of all cases of tuberculosis in immunocompetent patients and accounts for more than 50 per cent of the cases in HIV-positive individuals. Lymph nodes are the most common site of involvement followed by pleural effusion and virtually every site of the body can be affected. Since the clinical presentation of EPTB is atypical, tissue samples for the confirmation of diagnostic can sometimes be difficult to procure, and the conventional diagnostic methods have a poor yield, the diagnosis is often delayed. Availability of computerised tomographic scan, magnetic resonance imaging laparoscopy, endoscopy have tremendously helped in anatomical localisation of EPTB. The disease usually responds to standard antituberculosis drug treatment. Biopsy and/or surgery is required to procure tissue samples for diagnosis and for managing complications. Further research is required for evolving the most suitable treatment regimens, optimal duration of treatment and safety when used with highly active antiretroviral treatment (HAART).

Non small cell lung cancer (NSCLC): current status and future prospects

The incidence of lung cancer is rising dramatically and it is now the commonest cause of mortality and morbidity not only in the industrialised countries, but in developing nations like India as well. Tobacco smoking has consistently been demonstrated to be an important aetiological factor, though lung cancer occurs in non-smokers also. In spite of great advances in radiological and molecular diagnostic techniques, the ideal screening marker for early detection of lung cancer has still not been found. Histological diagnosis and staging is essential for selecting the mode of therapy in patients with lung cancer. Stages I and II are amenable to surgery. However, advanced stage III and IV need an individualised combination of surgery, chemotherapy and radiotherapy. With a better understanding of the cellular mechanisms operating in carcinogenesis, newer target specific modalities are being developed and tested in order to stem this disease, which threatens to assume epidemic proportions.

Uncommon manifestations of sarcoidosis

OBJECTIVE

To study the uncommon manifestations in patients of sarcoidosis.

METHODS

This is a prospective study of uncommon manifestations observed in 93 of the 210 biopsy proved patients (mean age 43.8 +/- 6.4 years; 58 males) of sarcoidosis seen by us over the last 22 years at the All India Institute of Medical Sciences, New Delhi.

RESULTS

Clinical presentation of acute sarcoidosis in the form of Löfgren's syndrome (n = 5) was uncommonly observed. Rare pulmonary manifestations included seasonal dyspnoea with audible wheezing mimicking bronchial asthma (n = 30); narrowing of main bronchi, fixed upper airways obstruction (n = 1); pleural involvement (n = 7); bullous lung disease (n = 2); chronic respiratory failure (n = 2); and vocal cord involvement (n = 4). Other notable features were glaucoma (n = 4); digital clubbing (n = 3); sarcoid nephritis (n = 1); and sicca syndrome (n = 1). Uncommon neurological manifestations included bilateral sequential facial nerve palsy (n = 2); optic atrophy (n = 2); optic neuritis, proximal myopathy, multiple brainstem lesions, pituitary stalk lesion (one patient each). Cardiac involvement occurred in 15 patients. This included complete heart block (n = 2); congestive heart failure (n = 4); supraventricular ectopics (n = 6); ventricular ectopics (n = 2); and recurrent ventricular tachycardia requiring radiofrequency ablation (n = 1). Contrast-enhanced computerised tomographic scan (CECT scan) of the abdomen revealed intrabdominal lymphadenopathy (n = 5); infiltrates in the liver and spleen (n = 3). Portal hypertension was observed in four patients with grade IV (n = 2) and grade II oesophageal varices (n = 2). One of the patients with grade IV oesophageal varices had recurrent haematemesis and successfully underwent endoscopic sclerotherapy while another patient with grade IV varices succumbed to massive haematemesis. CECT scan was found to be useful in localising the lesions in patients with extrapulmonary sarcoidosis.

CONCLUSION

Awareness regarding uncommon manifestations of sarcoidosis will facilitate early confirmation of diagnosis.

Does routine home visiting improve the return rate and outcome of DOTS patients who delay treatment?

Overa period of 6 months the effect of home visits on compliance with directly observed therapy, short course [DOTS], was studied on 480 new smear-positive tuberculosis patients who had delayed collecting their drugs on one occasion. Patients registered at 15 tuberculosis treatment centers in Baghdad, Iraq, were randomized to an intervention group [receiving home visits from trained personnel] or a control group. Home visits were highly effective in improving the return to treatment of patients who were late for treatment [231/240, 96.3%]. The intervention group showed a higher treatment success rate [94.2% versus 76.7%], lower default rate [0.8% versus 10.0%] and higher smear conversion rate after the end of treatment [92.9% versus 75.0%] than controls. Home visiting by trained personnel significantly improves patient compliance with DOTS