Identification and bioinformatic characterization of a serum miRNA signature for early detection of laryngeal squamous cell carcinoma.

BACKGROUND: The growing understanding of cancer biology and the establishment of new treatment modalities has not yielded the expected results in terms of survival for Laryngeal Squamous Cell Cancer (LSCC). Early diagnosis, as well as prompt identification of patients with high risk of relapse would ensure greater chance of therapeutic success. However, this goal remains a challenge due to the absence of specific biomarkers for this neoplasm. METHODS: Serum samples from 45 LSCC patients and 23 healthy donors were collected for miRNA expression profiling by TaqMan Array analysis. Additional 20 patients and 42 healthy volunteers were included for the validation set, reaching an equal number of clinical samples for each group. The potential diagnostic ability of the such identified three-miRNA signature was confirmed by ROC analysis. Moreover, each miRNA was analyzed for the possible correlation with HNSCC patients' survival and TNM status by online databases Kaplan-Meier (KM) plotter and OncomiR. In silico analysis of common candidate targets and their network relevance to predict shared biological functions was finally performed by PANTHER and GeneMANIA software. RESULTS: We characterized serum miRNA profile of LSCC patients identifying a novel molecular signature, including miR-223, miR-93 and miR-532, as circulating marker endowed with high selectivity and specificity. The oncogenic effect and the prognostic significance of each miRNA was investigated by bioinformatic analysis, denoting significant correlation with OS. To analyse the molecular basis underlying the pro-tumorigenic role of the signature, we focused on the simultaneously regulated gene targets-IL6ST, GTDC1, MAP1B, CPEB3, PRKACB, NFIB, PURB, ATP2B1, ZNF148, PSD3, TBC1D15, PURA, KLF12-found by prediction tools and deepened for their functional role by pathway enrichment analysis. The results showed the involvement of 7 different biological processes, among which inflammation, proliferation, migration, apoptosis and angiogenesis. CONCLUSIONS: In conclusion, we have identified a possible miRNA signature for early LSCC diagnosis and we assumed that miR-93, miR-223 and miR-532 could orchestrate the regulation of multiple cancer-related processes. These findings encourage the possibility to deepen the molecular mechanisms underlying their oncogenic role, for the desirable development of novel therapeutic opportunities based on the use of short single-stranded oligonucleotides acting as non-coding RNA antagonists in cancer.

Exosomes multiplex profiling, a promising strategy for early diagnosis of laryngeal cancer.

BACKGROUND: Exosomes are nanosized vesicles released from all cells into surrounding biofluids, including cancer cells, and represent a very promising direction in terms of minimally invasive approaches to early disease detection. They carry tumor-specific biological contents such as DNA, RNA, proteins, lipids, and sugars, as well as surface molecules that are able to pinpoint the cellular source. By the above criteria, exosomes may be stratified according to the presence of tissue and disease-specific signatures and, due to their stability in such biofluids as plasma and serum, they represent an indispensable source of vital clinical insights from liquid biopsies, even at the earliest stages of cancer. Therefore, our work aimed to isolate and characterize LCa patients' derived exosomes from serum by Flow Cytometry in order to define a specific epitope signature exploitable for early diagnosis. METHODS: Circulating exosomes were collected from serum collected from 30 LCa patients and 20 healthy volunteers by the use of antibody affinity method exploiting CD63 specific surface marker. Membrane epitopes were then characterized by Flow cytometry multiplex analysis and compared between LCa Patients and Healthy donors. Clinical data were also matched to obtain statistical correlation. RESULTS: A distinct overexpression of CD1c, CD2, CD3, CD4, CD11c, CD14, CD20, CD44, CD56, CD105, CD146, and CD209 was identified in LCa patients compared to healthy controls, correlating positively with tumor presence. Conversely, CD24, CD31, and CD40, though not overexpressed in tumor samples, showed a significant correlation with nodal involvement in LCa patients (p < 0.01). CONCLUSION: This approach could allow us to set up a cost-effective and less invasive liquid biopsy protocol from a simple blood collection in order to early diagnose LCa and improve patients' outcomes and quality of life.

TGF-ß Modulated Pathways in Colorectal Cancer: New Potential Therapeutic Opportunities.

Colorectal cancer (CRC) is the third most commonly diagnosed cancer worldwide, with 20% of patients presenting with metastatic disease at diagnosis. TGF-ß signaling plays a crucial role in various cellular processes, including growth, differentiation, apoptosis, epithelial-mesenchymal transition (EMT), regulation of the extracellular matrix, angiogenesis, and immune responses. TGF-ß signals through SMAD proteins, which are intracellular molecules that transmit TGF-ß signals from the cell membrane to the nucleus. Alterations in the TGF-ß pathway and mutations in SMAD proteins are common in metastatic CRC (mCRC), making them critical factors in CRC tumorigenesis. This review first analyzes normal TGF-ß signaling and then investigates its role in CRC pathogenesis, highlighting the mechanisms through which TGF-ß influences metastasis development. TGF-ß promotes neoangiogenesis via VEGF overexpression, pericyte differentiation, and other mechanisms. Additionally, TGF-ß affects various elements of the tumor microenvironment, including T cells, fibroblasts, and macrophages, promoting immunosuppression and metastasis. Given its strategic role in multiple processes, we explored different strategies to target TGF-ß in mCRC patients, aiming to identify new therapeutic options.

Microsatellite Instability: From the Implementation of the Detection to a Prognostic and Predictive Role in Cancers.

Microsatellite instability (MSI) has been identified in several tumors arising from either germline or somatic aberration. The presence of MSI in cancer predicts the sensitivity to immune checkpoint inhibitors (ICIs), particularly PD1/PD-L1 inhibitors. To date, the predictive role of MSI is currently used in the selection of colorectal cancer patients for immunotherapy; moreover, the expansion of clinical trials into other cancer types may elucidate the predictive value of MSI for non-colorectal tumors. In clinical practice, several assays are used for MSI testing, including immunohistochemistry (IHC), polymerase chain reaction (PCR) and next-generation sequencing (NGS). In this review, we provide an overview of MSI in various cancer types, highlighting its potential predictive/prognostic role and the clinical trials performed. Finally, we focus on the comparison data between the different assays used to detect MSI in clinical practice.

Sarcomatoid larynx carcinoma differential clinical evolution, on field statistical considerations.

Spindle cell larynx carcinoma (SpCC) represents around 3% of laryngeal cancers. It is originated by a single cancer stem cell undergoing epithelial to mesenchymal transition. This explains the aggressiveness, the peculiar resistance to conventional therapy and the frequent relapses. We focused on this particular cancer subset characteristics in patients, in early and advanced stages primarily aiming to define and highlight the differences with Laryngeal Squamous Cell Carcinoma (LSCC) focusing on clinical features, treatments, follow-up and survival in a patient's cohort composed by comparable cases from two subgroups.

Efficacy and Safety of Cetuximab plus Radiotherapy in Cisplatin-Unfit Elderly Patients with Advanced Squamous Cell Head and Neck Carcinoma: A Retrospective Study.

INTRODUCTION: Concurrent platinum-based chemoradiation currently represents the standard treatment for advanced head and neck cancer (HNC), but it induces a significant toxicity, in particular among elderly patients. Elderly and unfit patients have been underrepresented in clinical trials and there is a need for tailored guidelines. METHODS: A retrospective review of clinical data of HNC patients treated at the Operative Oncology Unit of the San Giovanni di Dio Hospital in Frattamaggiore (Naples, Italy) was performed. At study entry, a comprehensive assessment including absolute contraindications for cisplatin use, as well as comorbidities, socioeconomic status, BMI, and weight loss, was performed. The treatment included high-dose radiotherapy plus weekly cetuximab (initially at a dose of 400 mg/m2of body surface area and thereafter at 250 mg weekly during the whole radiotherapy). The aim of this study was to evaluate the activity and toxicity of this schedule in a series of patients aged older than 69 years. RESULTS: Between May 30, 2013, and March 30, 2015, sixty-four patients (age range, 69-87 years; median age, 73.7 years; male/female ratio, 46/18) were treated. The overall response rate was 67% in this series of patients. The disease control rate was 76%. Disease progression was recorded in 25% of the patients. The median duration of loco-regional control was 17 months (range, 15.8-17.7 months). PFS was 14.8 months (range, 13.9-15.5 months). The overall survival was 34 months, with a median follow-up of 41.0 months (range, 31.1-36.8 months). The main grade 3/4 adverse events were acne rash in 52% and radiation dermatitis in 32% of the cases. CONCLUSION: Cetuximab plus radiotherapy appears to be feasible and active in elderly patients unsuitable for cisplatin treatment. The treatment was supported by a favorable toxicity profile.

Maintenance Therapy with Biweekly Cetuximab: Optimizing Schedule Can Preserve Activity and Improves Compliance in Advanced Head and Neck Cancer.

OBJECTIVES: This study evaluates maintenance cetuximab administered every 2 weeks (q2w) after chemotherapy plus cetuximab as first-line treatment in a series of patients with head and neck squamous cell cancer and compares the results with those obtained in a historical control group of patients receiving weekly cetuximab. METHODS: After chemotherapy plus cetuximab as first-line treatment, in Group A, 36 patients enrolled from October 2016 to November 2017, received biweekly cetuximab, administered at 500 mg/m2. Group B was a control group of patients treated at our institution from August 2015 to September 2016 and received weekly infusion of cetuximab at 250 mg/m2. RESULTS: Confirmed overall response rates were, respectively, 19% for Group A and 17% for Group B according to intention-to-treat analysis. During the maintenance treatment, median progression-free survival (PFS) and median overall survival (OS) were similar for both groups (PFS, 4.8 and 4.4 months; OS, 9.0 and 7.9 months; in Groups A and B, respectively). The most common adverse events among treated subjects included fatigue, rash, and hypomagnesemia. CONCLUSION: Maintenance therapy with simplified biweekly cetuximab is a convenient, effective, and well-tolerated regimen in patients with recurrent and/or metastatic head and neck squamous cell carcinoma.

Adherence and safety of regorafenib for patients with metastatic colorectal cancer: observational real-life study.

AIM: In this prospective multicenter real-life observational cohort study, we investigated the acceptance, adherence and safety of regorafenib, in the treatment of metastatic colorectal cancer patients. PATIENTS & METHODS: A total of 136 patients were recruited at six oncological hospital sites in southern Italy. The adherence to the treatment was measured with patient-completed medication diaries, physician interviews and pill counts. RESULTS: We found a statistically significant improvement of therapy adhesion by the acceptance questionnaire. The Eastern Cooperative Oncology Group performance status, the level of acceptance, the educational level and the concomitant usage of oral medications influenced the adherence to the treatment. CONCLUSION: Patients' level of education, concomitant other oral medications and patients' general clinical condition may influence the adherence to regorafenib.

Metronomic oral vinorelbine in advanced breast cancer and non-small-cell lung cancer: current status and future development.

Metronomic chemotherapy (mCT), a frequent administration of low-dose chemotherapy, allows prolonged treatment duration and minimizes the toxicity of standard-dose chemotherapy. mCT has multiple actions against cancer cells including inhibition of angiogenesis and modulation of the immune system. A number of studies lend support to the clinical efficacy of mCT in advanced breast cancer and non-small-cell lung cancer. However, further evidence is necessary to describe the optimal use of mCT and to identify suitable patients. Oral vinorelbine has emerged as a promising metronomic treatment in patients with metastatic breast cancer and non-small-cell lung cancer and is the only orally available microtubule-targeting agent. This paper reviews current evidence on metronomic oral vinorelbine, discusses its management and defines a suitable patient profile on the basis of a workshop of Italian experts.

The role of immunotherapy in solid tumors: report from the Campania Society of Oncology Immunotherapy (SCITO) meeting, Naples 2014.

The therapeutic approach to advanced or metastatic solid tumors, either with chemotherapy or targeted therapies, is mainly palliative. Resistance to chemotherapy occurs very frequently and is one of the most important reasons for disease progression. Immunotherapy has the potential to mount an ongoing, dynamic immune response that can kill tumor cells for an extended time after the conventional therapy has been administered. Such a long-lasting response is potentially able to completely eradicate tumor cells, rather than producing only a temporary killing of cells. The most promising immune-based treatments are monoclonal antibodies that act as checkpoint inhibitors (e.g. ipilimumab and nivolumab), adoptive cell therapy (e.g. T-cells expressing chimeric antigen receptors) and vaccines (e.g. sipuleucel-T). Ipilimumab is currently approved for the treatment of metastatic melanoma and sipuleucel-T is approved for advanced prostate cancer. There is great interest in immunotherapy in other solid tumors, potentially used alone or in a multimodal fashion with chemotherapy and/or biological drugs. In this paper, we review recent advances in immuno-oncology in solid malignancies (except melanoma) as were discussed at the inaugural meeting of the Campania Society of Oncology Immunotherapy (SCITO).

Impact of anemia management with EPO on psychologic distress in cancer patients: results of a multicenter patient survey.

AIM: We investigated the role of erythropoietin (EPO) in reducing anemia and preventing the development of psychological distress in patients treated with chemotherapy. PATIENTS & METHODS: This prospective observational study enrolled 591 adult patients receiving EPO at a dose of 30,000 IU administered once weekly for chemotherapy-induced anemia (mean baseline hemoglobin [Hb] level was 9.55 g/dl) over a 12-month period. RESULTS: The majority of patients (371 [71%] patients) achieved a Hb increase >2 g/dl after 4 weeks of treatment. Interestingly, the nonresponder group had a statistically significant deterioration of their psychological conditions as indicated by psychological distress score (p = 0.01). However, within the group of responders to EPO, the Psychological Distress Inventory score remained unchanged. In the present study, severe side effects associated with EPO were not recorded. CONCLUSION: Hb increase, induced by EPO, ameliorates the psychological conditions of cancer patients.

Temozolomide based treatment in glioblastoma: 6 vs. 12 months.

The Stupp regimen remains the standard treatment for newly diagnosed glioblastomas, although the prognosis remains poor. Several temozolomide alternative schedules have been studied, with extended adjuvant treatment (>6 cycles of temozolomide) frequently used, although different trials have indicated contrasting results. Survival data of 87 patients who received 6 ('6C' group) or 12 ('12C' group) cycles of temozolomide were collected between 2012 and 2022. A total of 45 patients were included in the 6C group and 42 patients were included in the 12C group. Data on isocitrate dehydrogenase mutation and methylguanine-DNA-methyltransferase (MGMT) promoter methylation status were also collected. The 12C group exhibited statistically significantly improved overall survival [OS; 22.8 vs. 17.5 months; hazard ratio (HR), 0.47; 95% CI, 0.30-0.73; P=0.001] and progression-free survival (15.3 vs. 9 months; HR, 0.39; 95% CI, 0.25-0.62; P=0.001). However, in the subgroup analysis according to MGMT status, OS in the 12C group was significantly superior to OS in the 6C group only in the MGMT unmethylated tumors. The present data suggested that extended adjuvant temozolomide appeared to be more effective than the conventional six cycles.

MiR-449a antagonizes EMT through IL-6-mediated trans-signaling in laryngeal squamous cancer.

MicroRNAs (miRNAs) are involved in post-transcriptional gene expression regulation and in mechanisms of cancer growth and metastases. In this light, miRNAs could be promising therapeutic targets and biomarkers in clinical practice. Therefore, we investigated if specific miRNAs and their target genes contribute to laryngeal squamous cell carcinoma (LSCC) development. We found a significant decrease of miR-449a in LSCC patients with nodal metastases (63.3%) compared with patients without nodal involvement (44%). The AmpliSeq Transcriptome of HNO-210 miR-449a-transfected cell lines allowed the identification of IL6-R as a potential target. Moreover, the downregulation of IL6-R and the phosphorylation reduction of the downstream signaling effectors, suggested the inhibition of the IL-6 trans-signaling pathway. These biochemical effects were paralleled by a significant inhibition of invasion and migration in vitro and in vivo, supporting an involvement of epithelial-mesenchymal transition. These findings indicate that miR-449a contributes to suppress the metastasization of LSCC by the IL-6 trans-signaling block and affects sensitivity to external stimuli that mimic pro-inflammatory conditions.

Sorafenib in elderly patients with advanced hepatocellular carcinoma: a case series.

OBJECTIVE: The management of hepatocellular carcinoma (HCC) in elderly patients is significantly more complicated than in younger patients because of medical comorbidities, advanced status at diagnosis, reduced liver function and altered drug pharmacokinetics. Our objective was a revision of the charts of unselected elderly patients with HCC being treated with a reduced starting dose of sorafenib. METHODS: Activity, adverse events and quality of life were evaluated during the treatment. Sixty patients (47 males and 13 females) aged more than 70 years old (range 70-90, median 76 years) were retrospectively reviewed. RESULTS: One complete and one partial response were achieved in the series (overall response rate 3.3%). Stable disease accounted for 76.6% (46 out of 60 patients). The disease control rate (complete plus partial response plus stable disease) was 80%. Median time to progression (TTP) was 7.0 months (95% CI, 5.2-8.7 months) and median survival was 10.0 months (95% CI, 5.0-14.9 months). Thrombosis correlated to TTP. Full doses of sora-fenib were reached in 11 out of 60 patients (18.3%). The evaluation of quality of life did not show any significant change during the study. CONCLUSIONS: Sorafenib at a reduced dose can be safely used in elderly HCC patients with maintenance of activity and increased tolerability.

Identification of clinical predictive factors of oxaliplatin-induced chronic peripheral neuropathy in colorectal cancer patients treated with adjuvant Folfox IV.

PURPOSE: Oxaliplatin-induced neuropathy is a dose-related side effect which occurs in almost 40 % of patients treated with oxaliplatin. Aim of the present study was to identify reliable clinical factors predicting its development and duration. METHODS: One hundred sixty-nine completely resected colorectal cancer patients treated with adjuvant Folfox IV regimen were retrospectively included. The following pre-treatment clinical parameters were collected: hypocalcaemia, hypomagnesaemia, hypoalbuminaemia, anaemia, diabetes, chronic renal failure (CRF), folate deficiency, vitamin B(12) deficiency, number of cycles received and habit to alcohol consumption. Incidence, grade (NCI-CTCAE v.3) and duration of neuropathy were recorded. RESULTS: Incidence of neuropathy was found to be higher in patients with pre-treatment anaemia (p = 0.001), hypoalbuminaemia (p = 0.01) and hypomagnesaemia (p = 0.001) as well in those with habit to alcohol consumption (p = 0.003). Neuropathy durations were conversely associated with age, being longer in younger patients (p = 0.03), and again with hypoalbuminaemia (p = 0.04) and hypomagnesaemia (p = 0.002). No correlation was found with gender, hypocalcaemia, diabetes and CRF. The correlation between vitamin B(12) and folate levels and the development of neurotoxicity were not analysed because of the high number of missing data in the population. CONCLUSIONS: Age, anaemia, hypoalbuminaemia, hypomagnesaemia and alcohol consumption are reliable and easily assessable clinical factors predicting incidence and length of oxaliplatin-induced neuropathy.

Prognostic value of diabetes and metformin use in a real-life population of head and neck cancer patients.

Introduction: Head and neck carcinoma (HNC) is a disease with a poor prognosis despite currently available treatments. The management of patients with this tumor is often complicated by several comorbidities. Among these, diabetes is the second most frequent and its influence on the prognosis is not known. Methods: In this work, we collected data on progression free survival (PFS) and overall survival (OS) of one hundred twenty-three patients with HNC who received biweekly cetuximab maintenance treatment after first-line chemotherapy. We then compared the survival of nondiabetic patients versus diabetics' one. Results: Surprisingly, both PFS (4 vs. 5 months, HR 2.297, p < 0.0001) and OS (7 vs. 10 months, HR 3.138, p < 0.0001) were in favor of diabetic patients, even after excluding other clinical confounding factors. In addition, we also studied survivals in patients taking metformin, a widely used oral antidiabetic drug that has demonstrated antitumor efficacy in some cancers. Indeed, diabetic patients taking metformin had better PFS and OS than those not taking it, 7 vs. 5 months (HR 0.56, p = 0.0187) and 11 vs. 8.5 months (HR 0.53, p = 0.017), respectively. Discussion: In conclusion, real-world outcomes of biweekly cetuximab maintenance remain comparable to clinical trials. The prognostic role of diabetes and metformin was confirmed to be significant in our series, but further prospective studies are needed for a definitive evaluation.

Utility of psychotherapy assessed with Kessler scale in a population of cancer patients undergoing systemic oncological treatment: a mono-institutional experience.

BACKGROUND: Psychological distress has been associated with greater physical symptom severity, suffering, and mortality in cancer patients. For this reason, today, psychological care represents a fundamental tool for improving the quality of life of cancer patients. METHODS: From September 2021 to May 2022, 170 newly diagnosed cancer patients, were enrolled in the observational study at Medical Oncology Unit, "San Giovanni di Dio" Hospital. Before the start of oncological treatment, they were subjected to the Kessler 10 (K10) test, a validated measure of non-specific symptoms of psychological distress of the past 4 weeks. On the basis of the score, they were divided into three groups: low [10-19], moderate [20-29] and high [30-50] distress. After 3 months of psychological therapy, they repeated the test. RESULTS: Majority of patients were female (74.1%), aged <70 years (78.2%). The most represented tumours were breast (47.6%), colon (15.3%), urothelial (10.6%) and lung (7.6%) cancer and most patients started intravenous chemotherapy treatment (74.7%) rather than oral therapy. The previous remote pathological history and the family cancer history of the patients were also evaluated. Finally, marital status, schooling and employment status were recorded. At baseline we found 55, 72, and 43 patients with a low, moderate and high psychological distress, respectively. After the 3 months of psychotherapy, we re-administered the K10 test and we found a radical improvement in the degree of psychological distress (96 patients had a low score, 62 with a moderate score and just 12 patients with a high score). The great reduction in the score in K10 was statistically significant with a P value of <0.0001. The reduction of the K10 score was observed indiscriminately in all subgroups analysed. A statistically significant difference was observed between patients with different education levels (low 56% vs. high 32% of reduction in K10 score). Furthermore, the improvement in psychological health was greater in unemployed patients than in workers. CONCLUSIONS: The use of the K10 test is helpful in monitoring the degree of psychological distress of patients facing the diagnosis of cancer and who are about to start oncological treatment. Psychotherapy is effective in reducing the distress of these patients just a few months after starting treatment.

Clinical activity of regorafenib in elderly patients with recurrent glioblastoma.

Glioblastoma multiforme is one of the most frequent and aggressive primary tumors in the central nervous system, representing >60% of all brain tumors in adults. Despite treatment, prognosis remains poor with most if not all patients experiencing disease recurrence and a 2-year survival rate of 27%. At present, no confirmed standard treatment exists for recurrent glioblastoma. Regorafenib is one of the few options available, based on results from the REGOMA trial. In the present study, a real-life retrospective investigation on the role of regorafenib in patients with recurrent glioblastoma (>60 years old) from two main Oncological Units in South Italy (Azienda Ospedaliera Universitaria Luigi Vanvitelli, Naples, Italy and Ospedale Civile San Giovanni di Dio, Frattamaggiore, Naples, Italy), was performed. The primary endpoint was overall survival (OS), whereas progression-free survival (PFS), objective response rate and disease control were secondary endpoints. Survival was then analyzed according to age, isocitrate dehydrogenase (IDH) and methylated methylguanine-DNA-methyltransferase (MGMT) status. A total of 56 patients met the eligibility criteria. The intention to treat population median PFS (mPFS) was 4.1 months and median OS (mOS) was 6.8 months. Age did not appear to have a significant influence on mPFS. mOS in MGMT-methylated patients was improved compared with that of the unmethylated group (7.7 months vs. 5.6 months). Both mOS and mPFS were longer in IDH-mutant patients. The present study was one of the first real life analyses of regorafenib in recurrent glioblastoma. The results were in line with the REGOMA trial. Age did not appear to be a prognostic factor, thus suggesting that treatment choice should not be different in elderly. MGMT methylation appeared to influence OS. To the best of our knowledge, this was the first report of regorafenib activity in older patients and, while the results were statistically significant, these should be confirmed in further studies.

A delayed complication of a port-a-cath insertion via subclavian venous access: Case report of a "pinch-off syndrome".

INTRODUCTION: Port-a-caths are long-stay central catheters often used for chemotherapy or parenteral nutrition. The implantation of a port-a cath, despite being involved in routine procedures, is also associated with immediate and delayed complications. Complications are rare but must be known and managed by operators. CASE REPORT: A delayed complication related to the presence of a port-a-cath, consisting in the fragmentation of the catheter, has been reported, in a 63-years-old female patient. The port was placed via subclavian venous access and affected by pinch-off syndrome, which resulted in catheter malfunction and then in fragmentation from compression by the subclavius-costoclavicular complex. The onset symptom was device malfunction. DISCUSSION AND CONCLUSION: The focus in the management of this rare but possible complication was the quick removal of the device and of the catheter fragment in the endovascular lumen with collaboration between different medical specialists.