Handling the Cellular Complex Systems in Alzheimer's Disease Through a Graph Mining Approach.

In the last two decades, the medical sciences have changed their approach to pathogenesis as well as to the diagnosis and treatment of complex human diseases. The main reason for this change is the explosive development of biomedical technology and research, which produces a huge amount of information and data which are generated at an increasing rate. Toward this direction is the pathway analysis, a thriving research area of systems biology tools and methodologies which aim to unravel the inherent complexity of high-throughput biological data produced by the advent of omics technologies. Through this graph mining approach, we can deal with the complexity of the cellular systems of various diseases such as Alzheimer's disease. In this work, we developed a subpathway analysis method for single-cell RNA-seq experiments which isolates differentially expressed subpathways indicating potentially perturbed biological processes. The differential expression status of each gene is negotiated among well-established RNA-seq differential expression analysis tools in order to minimize false discoveries. Also, we demonstrate the efficacy of our method on a single-cell RNA-seq dataset for temporal tracking of microglia activation in neurodegeneration. Results suggest that our approach succeeds in isolating several perturbed biological processes known to be associated with neurodegeneration.

Emerging Machine Learning Techniques for Modelling Cellular Complex Systems in Alzheimer's Disease.

We live in the big data era in the biomedical field, where machine learning has a very important contribution to the interpretation of complex biological processes and diseases, since it has the potential to create predictive models from multidimensional data sets. Part of the application of machine learning in biomedical science is to study and model complex cellular systems such as biological networks. In this context, the study of complex diseases, such as Alzheimer's diseases (AD), benefits from established methodologies of network science and machine learning as they offer algorithmic tools and techniques that can address the limitations and challenges of modeling and studying cellular AD-related networks. In this paper we analyze the opportunities and challenges at the intersection of machine learning and network biology and whether this can affect the biological interpretation and clarification of diseases. Specifically, we focus on GRN techniques which through omics data and the use of machine learning techniques can construct a network that captures all the information at the molecular level for the disease under study. We record the emerging machine learning techniques that are focus on ensemble tree-based techniques in the area of classification and regression. Their potential for unraveling the complexity of model cellular systems in complex diseases, such as AD, offers the opportunity for novel machine learning methodologies to decipher the mechanisms of the various AD processes.

Biomarkers as a Different Approach in Prevention and Treatment of Drug Addiction (Preliminary Study).

Drug addiction is a chronic relapsing disorder and a burden to society and individuals. The toxicity induced by drugs related with addiction may trigger dysfunction and death of cells of the central nervous system. The study of alterations of proteins and biomarkers in buccal cells would be beneficial in understanding drug addiction, as the buccal mucosa is of ectodermal origin such as the central nervous system. METHOD: Buccal smears of 35 individuals with addictive disorders (20) or substance use disorders (15) for more than 3 years were collected by the gentle brushing of the inside of the cheeks. Immunocytochemical staining of IL-1ß, IL-6, TNF-α, NFKß, bcl-2, and ucp4 was performed on the epithelial cells, for the study of oxidative stress, toxicity, and inflammation. Papanicolaou staining was also performed for the potential structural disorders. There was a correlation with the clinical profile of each individual. None of the individuals was HIV or Tbc positive. RESULTS: Cytomorphology and immunoprofile of the smears of chronic relapsers and substance users for more than 3 years revealed karyolitic cells undergoing necrosis and increased expression of the markers IL-1ß, IL-6, TNF-α, and NFKß. Decreased expression of bcl2 was correlated with increased expression of ucp4. CONCLUSION: The literature in the area of addiction is growing rapidly; however, the results are still mixed. Given the complexity of the problem, the goal should be the discovery of a minimal invasive and inexpensive diagnostic procedure to identify a prognostic and therapeutic target. The correlation of the expression of biomarkers on buccal cells could be valuable for the design of predictive and therapeutic strategies.

Enhancer of zeste homologue 2 expression in breast carcinoma smears in relationship with p53, Ki-67 and other prognostic parameters.

BACKGROUND: The polycomb group protein enhancer of zeste homologue 2 (EZH 2) has been reported as a marker of aggressive breast cancer. The aim of this study was to investigate the correlation between the expression of EZH 2 with p53 and Ki-67 expression and other clinicopathological parameters in primary breast carcinomas in order to determine the role of the above marker as a prognosticator of tumor aggressiveness and patient outcome. PATIENTS AND METHODS: One hundred primary operable breast cancer patients were investigated in order to identify the expression of EZH 2, Ki-67 and p53 in imprint smears immunocytochemically. The prevalence of expression of these markers was then correlated with clinicopathological parameters. Follow-up was available for all patients. RESULTS: EZH 2 was expressed in 64% of the cases and correlated with higher levels of p53 (relative risk = 3.00, p < 0.0001) and Ki-67 (relative risk = 3.25, p < 0.0001). Malignant cells showed immunoreactivity for all markers in the nucleus. Univariate analysis revealed a strong association between EZH 2 protein expression and tumor grade and size, lymph node metastasis, and HER-2 and estrogen and progesterone receptor status. Multivariable statistical analysis revealed that lymph node metastasis was the main predictor for EZH 2 expression. Decreased patient survival was also significantly associated with EZH 2 expression (p < 0.0001). CONCLUSIONS: EZH 2 expression may be a marker of poor prognosis in breast carcinoma patients and has been suggested as a candidate for targeted therapy.

Extramedullary Leukemia, Presenting at the Cervix of the Uterus.

Extramedullary relapse of leukemia is encountered more often than in the past. The reason is that leukemia survival rates increase with improved treatment schemes. We present a rare case of involvement of the cervix of the uterus in an adult B Acute Lymphocytic Leukemia (B-ALL) survivor. Relapses affect various organs but rarely the female genital tract. Nevertheless, in this case, a woman with a history of induced amenorrhea due to treatment for leukemia presented to the gynecologist because of vaginal spotting. Colposcopy evaluation of the vagina/cervix, sonography and cytological and histological sampling established the diagnosis of leukemia relapse in the cervix of the uterus. Under these circumstances, our study highlights the rare extramedullary presentation of leukemia in the cervix of the uterus of a young lady considered to be disease-free and listed for bone marrow transplantation. In this rare case of relapse in the cervix of the uterus, Pap smears alarmed physicians, and radiology examinations assisted the diagnostic workup. Still, only biopsy, microscopic evaluation, and immunohistochemistry studies established the exact diagnosis. Prognosis in the situation of extramedullary disease relapse in the female genital tract was poor, but gynecologists' high suspicion led to a prompt diagnosis. Survival is in general limited, but together with high suspicion, multidisciplinary team involvement is imperative to improve the reduced chances of survival.

Telomerase RNA expression and DNA ploidy as prognostic markers of prostate carcinomas.

AIMS AND BACKGROUND: The objective of this study was to determine whether there was a correlation between telomerase RNA expression and DNA ploidy status with clinicopathological parameters and biochemical recurrence after radical prostatectomy. STUDY DESIGN: Telomerase RNA expression and DNA ploidy were evaluated in imprint smear samples obtained from 112 prostates after radical prostatectomy. The results were correlated with pathological stage, Gleason score and serum PSA. RESULTS: Positive telomerse RNA expression was detected in 67.8% of prostate carcinomas. The multiple linear regression model showed a statistically significance increase in telomerase RNA expression with increased Gleason score (P < 0.0001) and preoperative serum PSA values (P = 0.0125). DNA ploidy status also varied significantly with Gleason score (P < 0.0001) and preoperative serum PSA values (P = 0.0110). Five patients with diploid tumors and negative telomerase RNA expression developed a recurrence. However, recurrence was associated with DNA aneuploidy (P = 0.001) as well as with high telomerase RNA overexpression (P = 0.001). CONCLUSIONS: We conclude that telomerase RNA expression and DNA ploidy could be additional markers in the field of prognosis of prostate carcinomas.

The prognostic significance of COX-2 and survivin expression in ovarian cancer.

We investigated the prognostic significance of cyclooxygenase-2 (COX-2) and survivin in ovarian carcinoma. Imprint smears were obtained from 100 ovarian carcinoma specimens and were studied immunocytochemically for the expression of COX-2 and survivin. The results were correlated with several clinicopathological parameters, including 5-year survival. Increased COX-2 staining pattern correlated with a non-mucinous histological type (p=0.008), increased stage (p<0.0001), high histological grade (p<0.0001), and reduced survival rates (p<0.00001). Survivin expression was strongly associated with increased stage (p<0.0001), increased histological grade (p<0.0001), and reduced survival (p<0.00001). Elevated survivin expression also correlated significantly with pre-menopausal status (p=0.033). In addition, COX-2 and survivin staining patterns correlated strongly with one another (p<0.0001). However, on multivariate analysis, an independent prognostic value was found only for tumor stage and grade. The findings of our study indicate that the increased expression of COX-2 and survivin in ovarian cancer is associated with one another and with several adverse clinicopathologic parameters, including reduced survival, thus suggesting a role of these molecules in disease progression. Further investigations of the exact prognostic and therapeutic implications of COX-2 and survivin expression are strongly warranted.

The expression of metallothioneins on imprint smears of prostate carcinoma: correlation with clinicopathologic parameters and tumor proliferative capacity.

AIMS AND BACKGROUND: Metallothioneins are a family of metalbinding cysteine-rich proteins that play an important role in cellular processes such as proliferation and apoptosis, protection against oxidative stress and metal ion homeostasis and detoxification. Recent findings suggest that metallothioneins might play a significant role in the development and progression of prostate cancer. It has been also demonstrated that Ki67 expression may have prognostic value for disease-free survival in cases of prostate carcinoma. STUDY DESIGN: Imprint smears samples obtained from 70 patients immediately after radical prostatectomy for prostatic carcinoma were immunostained with monoclonal antibodies against metallothioneins and Ki-67. Metallothionein expression was correlated with Ki-67 immunostaining, Gleason score, stage, preoperative prostate-specific antigen levels and biochemical recurrence. RESULTS: Metallothionein expression was shown to correlate strongly with Gleason score (P < 0.001) and significantly with pathological staging and Ki-67 immunostaining (P < 0.001, P < 0.05, respectively). In contrast, no significant association between metallothioneins and preoperative PSA was demonstrated. Both of the studied markers (metallothioneins and Ki-67) correlated with recurrence (P = 0.009, P = 0.006, respectively). CONCLUSIONS: The present findings support the independent predictive value of metallothioneins and Ki-67 in prostate cancer. However, additional data are needed in order to reveal the factors that influence the expression of metallothioneins in epithelial neoplastic cells and clarify their mechanism of action.

Cytokeratin 8 and 18 expression in imprint smears of chronic viral hepatitis, autoimmune hepatitis and hepatocellular carcinoma. A preliminary study.

OBJECTIVE: To investigate whether the expression of cytokeratin (CK) 8 and 18 is altered in chronic active viral hepatitis, autoimmune hepatitis and hepatocellular carcinoma. STUDY DESIGN: Cytologic imprint smears were obtained from 53 liver core biopsy specimens and were studied immunocytochemically for the expression of CK8 and 18. RESULTS: CK8-positive expression was observed in 45.5% of chronic active hepatitis B (CH-B), 20% of chronic active hepatitis C (CH-C), 90% of autoimmune hepatitis (AIH) and 83.3% of hepatocellular carcinoma (HCC) cases. CK18-positive expression was observed in 36.4% of CH-B, 26.7% of CH-C, 70% of AIH and 83.3% of HCC cases. A statistically significant association was found between CK8- and CK18-positive expression and the diagnosis of AIH and HCC. In contrast, CH-C and CH-B were associated with negative CK8 and CK18 expression. In addition, a negative [CK8(-)/CK18(-)] or imbalanced [CK8(-)/CK18(+), CK8(+)/CK18(-)] expression pattern was found in 100.0% and 81.18% of CH-C and CH-B cases, respectively, while the relative percentages of AIH and HCC cases were significantly lower (30.0% and 16.7%, respectively) (p < 0.0001). CONCLUSION: Our results indicate that CK8 and 18 expression is maintained in AIH and HCC and altered in CH-B and CH-C. The pathogenetic mechanism of this alteration remains to be clarified.

[Serum testosterone, dihydrotestosterone, luteinizing hormone and follicle-stimulating hormone versus prostate specific antigen in patients with localized prostate adenocarcinoma who underwent radical prostatectomy. Radioimmunoassays measurements].

The relation of steroid hormones (SH) with carcinogenesis is not well understood. There is a variation of opinions among researchers about the prognostic value of serum SH in patients with localized prostate cancer (PC). The aim of this was to study serum SH in patients with localized PC before and after radical prostatectomy (RP). Seventy patients with mean age 67+/-8 years, were studied. The diagnosis was confirmed by histology after a biopsy. None of the patients was submitted to hormonal treatment or radiotherapy prior to RP. Serum testosterone (TST), dihydrotestosterone (DHT), luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels were examined prior RP and one year following RP, by radioimmuno assay (RIA) or immunoradiometric assay (IRMA) methods. Based on serum PSA levels before and one year after RP, 66 of the patients did not have biochemical recurrence while 4 patients developed biochemical recurrence due to residual disease and were treated with flutamide and a LH-RH analogue. In the group of 66 patients there was a statistically significant increase in serum TST (P<0.001), LH (P=0.004) and FSH (P<0.001), and statistically significant decrease in serum DHT (P<0.001). In the four patients with biochemical recurrence, TST increased and serum DHT, LH and FSH decreased. In this group the reduction of DHT and LH, FSH were due to treatment with flutamide and a LH-RH analogue respectively. Our findings suggest that after RP increase of serum LH and FSH may have caused an increase in serum TSH and a decrease of serum DHT. If those changes are due to the hypothalamic-pituitary axis it may be that the prostate neoplasm before RP may have secreted a substance that induced a negative feedback to the pituitary gonadotrophin secretion, which was unrelated to varying serum PSA levels.

Immunocytochemical expression of a panel of markers in pleural effusions from patients with primary lung adenocarcinoma.

INTRODUCTION: This study's principal objective was to evaluate the critical role of the application of immunocytochemistry to a novel panel of diagnostic markers for the accurate detection of the source of malignancies in pleural effusions of lung adenocarcinoma. MATERIALS AND METHODS: In 40 effusion smears from lung adenocarcinoma, the expression of the E-cadherin, a-catenin, Thyroid Transcription Factor (TTF-1), Epidermal Growth Factor Receptor (EGFR), p53, caspase 9 and 3, Bax and Bcl-2 was examined by immunocytochemistry. RESULTS: All cases showed positive immunoreactivity of tumour cells to caspase 3 (42,5%), caspase 9 (40%), Bcl-2 (30%), Bax (40%), p53 (55%), E-cadherin (82,5%), a-catenin (80%), TTF-1 (87,5%) and EGFR (62,5%). The Pearson's x2 analysis demonstrated a highly significant correlation to each of the other marker when analysed separately. Caspase 3 expression was correlated significantly with caspase 9 (p<0.0001), Bax (p=0.002), Bcl-2(p=0.014) and p53 (p=0.011). Caspase 9 was correlated with Bax (p=0.005) and p53 (p=0.047), p53 correlated with E-cadherin (p=0.011), a-catenin(p=0.011), EGFR (p<0.0001) and Bax (p=0.032). Correlation was also observed between Bcl-2 and Bax expression (p<0.0001), E-cadherin and a-catenin expression (p<0.0001) and a-catenin and TTF-1 expression (p=0.002). CONCLUSIONS: The use of a panel of biomarkers can be of great value in determining effusion immunoprofile in patients with lung adenocarcinoma for clinical application.

Prognostic value of COX-2, P53, and EZH-2 evaluated by quantitative image analysis in premalignant and malignant breast lesions.

BACKGROUND: Cytological differential diagnosis of atypical hyperplasia and well differentiated breast carcinoma may be challenging, because sometimes there is an overlap between the cytomorphological features of these lesions. The aim of the study was to investigate COX-2, EZH-2, p53 expression in carcinomas and the gray zone of breast cytology categories of atypical hyperplastic lesions with regard to biological behavior of the tumor. METHODS: FNA speciments from 100 patients with breast hyperplastic lesions and cancer were investigated by immunocytochemistry and a quantitative analysis for COX-2, p53, and EZH-2. RESULTS: Extent of staining for COX-2 correlated with percentage of positive for EZH-2 (P < 0.0001) and p53 nuclei (P < 0.001). The intensity of COX-2 was lower in the carcinoma group (118.57 ± 12.43) than in the hyperplastic (127.16 ± 11.71) group (P = 0.006). On the contrary the mean value of staining extent was greater in the adenocarcinoma cases (15.96 ± 13.03) than in hyperplastic (4.04 ± 1.94) cases (P < 0.0001). The percentage of EZH-2 and p53 positive cells correlated with the histological type of the lesions (P = 0.001 and P = 0.011, respectively). There was also a statistically significant relation between tumor size and expression of COX-2 (P = 0.007) and EZH-2 (P = 0.010). CONCLUSION: Our study showed that the expression of COX-2, EZH-2, and p53 as determined by immunocytochemistry at quantitative level may be a predictor for distinguishing cytologically atypical hyperplastic from malignant breast lesions and may be regarded as potential prognostic factor in breast cancer patients.

The significance of Survivin and Nectin-4 expression in the prognosis of breast carcinoma.

To investigate the prognostic significance of Survivin and Nectin-4 expression in breast carcinomas. Imprint smears were obtained from 140 breast carcinoma specimens and studied immunocytochemically for the expression of Survivin and Nectin-4. The results were correlated with several clinicopathological parameters, including five-year survival. Increased Survivin staining pattern correlated with increased grade (p < 0.0001), increased lymph node invasion (p < 0.0001), increased tumor size and reduced survival (p < 0.0001). Elevated Nectin-4 expression also correlated significantly with increased grade (p < 0.0001), increased tumor size (p < 0.0001) and reduced survival (p < 0.0001). In addition, Survivin and Nectin-4 staining patterns correlated strongly with one another (p < 0.0001). However, on multivariate analysis, neither Survivin nor Nectin-4 expression seemed to have an independent impact on survival in our study cases. The findings of our study suggest that increased expression of Survivin and Nectin-4 may indicate a worse prognosis in breast cancer patients. The exact implications of the expression of these markers in breast cancer prognosis and treatment remain to be clarified.

Mitochondrial UCP4 and bcl-2 expression in imprints of breast carcinomas: relationship with DNA ploidy and classical prognostic factors.

Mitochondria are the bioenergetic and metabolic centers of cells and play an important role in the regulation of cell death. The mitochondrial apoptosis pathway is controlled by the bcl-2 protein family. Overexpression of mitochondrial uncoupling protein 4 (UCP4) can promote proliferation and inhibit apoptosis and differentiation. Imprint smears obtained from 124 tumors were studied immunocytochemically, and results were correlated with prognostic markers. There were 112 ductal and 12 lobular carcinomas. The positivity of UCP4 was correlated with lymph node metastases (p=0.005), positive ER and PR expression (p<0.0001 for both), as well as positivity for p53 (p<0.0001) and Ki-67 (p<0.0001). Decreased expression of bcl-2 correlated with increased expression of UCP4 (p=0.001). Regarding DNA ploidy, UCP4 positivity was correlated with aneuploid tumors (p=0.002). Negative expression of bcl-2 was correlated with poorly differentiated carcinomas (p<0.0001), as well as with positive expression of p53 (p<0.0001) and Ki-67 (p<0.0001). Logistic regression revealed that ploidy and p53 expression had an impact on UCP4. These findings encourage future investigations regarding the potential role of UCPs not only into mechanisms underlying breast cancer, but also as a novel candidate to the design and development of more effective therapeutic strategies.

The value of E-cadherin/beta-catenin expression in imprints of NCSLC: relationship with clinicopathological factors.

Metastasis is specific for malignant tumors and its control is one of the most important problems in the design of therapies for cancer patients. Loss or reduction of E-cadherin expression and/or beta-catenin expression plays a casual role in tumor progression and metastasis and is associated with poor prognosis. The purpose of the study is to investigate the expression of E-cadherin and beta-catenin and their significance as independent prognostic markers in imprints of resected nonsmall cell lung cancer (NSCLC). Imprint smears from 70 patients who underwent surgical lung resection for primary carcinoma were studied. As control group was used imprints of physiological tissues. Histologically 47 (67.1%) of the tumors were squamous cell carcinomas and 23 (32.9%) were adenocarcinomas. Tumors stage was I in 29 (41.4%), II in 13 (18.6%), III in 24 (34.3%) and IV in 4 (5.7%). Positive expression for E-cadherin was observed in 44.29% of malignant smears vs 85.71% for control group (P = 0.011). For beta-catenin, positive expression was observed in 42.86% malignant cases vs 85.71% for control group (P = 0.008). Positive expression of E-cadherin and beta-catenin was observed in moderate and well differentiated tumors (P < 0.0001 for both respectively). Positive E-cadherin and beta-catenin expression was observed in 70.6% and 76.5% of the cases with negative lymphnode metastasis (P < 0.0001 for both respectively). There was no statistically significant association between histological type, tumor stage, pleural invasion, tumor size (P > 0.05 for all) and E-cadherin/beta-catenin expression.Reduced E-cadherin or beta-catenin negative expression relates to dedifferentiation and progression of NSCLC.

CD24 expression has a prognostic impact in breast carcinoma.

We investigated the prognostic significance of BAG-1 and CD24 in invasive breast carcinomas. Seventy cases of invasive breast carcinoma were studied immunocytochemically for the expression of BAG-1 and CD24. The results were correlated with several prognostic parameters, including 5-year survival. Univariate analysis showed a significant correlation of BAG-1 and CD24 overall positive staining with several adverse prognostic parameters, such as increased stage (p<0.0001), tumor grade 3 (p=0.016 and p=0.02, respectively), positive lymph nodes (p<0.0001), and increased tumor size (p<0.0001). Similar results were found for BAG-1 nuclear staining, as well as for positive cytoplasmic CD24 expression. Both of our markers studied had a significant, negative effect on survival. Multivariate analysis further revealed an independent prognostic impact for CD24 overall staining. The results of our study showed that overall cytoplasmic and especially nuclear BAG-1 expression, as well as overall and cytoplasmic CD24 expression, correlates with adverse prognostic parameters. An independent prognostic value for overall CD24 staining was also demonstrated.

Apoptotic and inflammation markers in oral mucositis in head and neck cancer patients receiving radiotherapy: preliminary report.

GOAL OF WORK: The aim of this study was to investigate the expression of pro-apoptotic protein p53 and anti-apoptotic proteins BCl-2 and MCl-1, as well as the expression of pro-inflammatory cytokines tumor necrosis factor (TNF) and interleukin-1beta (IL-1beta) in patients developing mucositis during radiotherapy for head and neck cancer. MATERIALS AND METHODS: Thirty-five patients receiving radiotherapy for head/neck cancer were included in this study. Patients were examined before radiotherapy. Oral mucositis was recorded weekly during radiotherapy. Cytologic smears from the oral cavity were taken with a brush. Immunocytochemical staining was performed by the use of p53, BCl-2, MCl-1 TNF and IL-1beta monoclonal antibodies. MAIN RESULTS: P53 was expressed in 1 of 15 smears before the initiation of radiotherapy (6.5%) compared to 3 of 7 smears from patients with grade III mucositis (43%) during radiotherapy. BCl-2 was expressed in 15 of 15 smears before radiotherapy (100%) and in three of seven patients with grade III mucositis (43%) during radiotherapy. MCl-1 was expressed in 10 of 14 samples before radiotherapy (71.5%) and in two of seven patients with grade III (28.5%) mucositis during radiotherapy. TNF was expressed in 9 of 14 patients before radiotherapy (64%) and in six of seven patients with grade III mucositis during radiotherapy (86%). IL-1beta was detected in 7 of 14 patients before radiotherapy (50%) compared to 6 of 7 patients with grade III mucositis during radiotherapy (86%). CONCLUSION: Our preliminary results indicate an induction of apoptosis and inflammation in the oral mucosa in patients developing mucositis during radiotherapy for head/neck cancer.

Herpes simplex virus-1 (HSV-1) infection in radiation-induced oral mucositis.

GOAL OF WORK: The aim of the study was to investigate the incidence of herpes simplex virus-1 (HSV-1) infection in mucositis during head and neck cancer radiotherapy. PATIENTS AND METHODS: Sixty patients with malignant head and neck tumor, eligible to receive radiotherapy, who were referred to the Dental Oncology Unit, entered the study. Sixteen patients (26.6%) received concomitant chemotherapy. Mucositis was recorded weekly. Smears taken from the ulcers of mucositis grade 2, or 3, or 4 were stained with Papanicolaou and alkaline phosphatase/antialkaline phosphatase immunocytochemical method to identify HSV-1. MAIN RESULTS: Forty-eight of all 60 patients developed ulcerative mucositis. Smear was available from 29 of 48 patients with ulcerations. HSV-1 infection was identified in 14 of 29 smears available (48.2%). Mucositis healed or was reduced after 1 week of antiviral treatment in 11 of those 14 HSV-1-positive patients; 3 patients responded to 1 g/day of valacyclovir, 7-2 g/day, and 1 patient responded to i.v. acyclovir. Ulcerations recurred after quitting antivirals. Three patients did not respond to 1 g/day of valacyclovir. No HSV-1-negative patient responded to acyclovir (P = 0.000). CONCLUSION: HSV-1 was isolated from 14 of 29 available smears taken from 48 patients with ulcerative mucositis. The incidence of HSV-1 infection during radiotherapy was estimated as being 14 of all 48 patients at risk (29.1%). Healing or reduction in the grade of mucositis after antivirals in HSV-1 positive patients, combined with the negative response to antivirals in HSV-1 negative patients, denoted that HSV-1 infection was a component of ulcerative radiation mucositis in those HSV-1-positive patients.