M.L.B. Bhatt

Oral cancer: risk factors and molecular pathogenesis.

IntroductionOral cancer is one of the most common cancers and it constitutes a major health problem particularly in developing countries. It is one of the leading causes of death. Tobacco and alcohol consumption appears to be the major determinants of oral cancer.Materials and methodsThe literature search was carried out in NCBI Pubmed database using keywords “oral cancer”, “risk factor”, “epidemiology” and “patho*”. Some basic information was also obtained from textbook and medical university websites.ResultsSeveral risk factors have been well characterized to be associated with oral cancer with substantial evidences. The development of oral cancer is a multistep process involving the accumulation of genetic and epigenetic alterations in key regulatory genes. Experimental pathological studies of oral cancer in animal models and direct molecular genetic analysis of oral cancer subjects in recent times have revealed a substantial amount of knowledge on specific gene alterations or other genetic mechanisms involved in initiation and subsequent progression.ConclusionConsidering known risk factors, oral cancer appears to be to a certain extent, a preventable disease. Recent development of molecular picture of pathoprogression and molecular genetic tools opens the avenue for easier diagnosis, better prognostication and efficient therapeutic management.

Centchroman inhibits proliferation of head and neck cancer cells through the modulation of PI3K/mTOR pathway.

Centchroman (CC; 67/20; INN: Ormeloxifene) is a non-steroidal antiestrogen extensively used as a female contraceptive in India. In the present study, we report the anti-proliferative effect of CC in head and neck squamous cell carcinoma (HNSCC) cells. CC inhibited cell proliferation in a dose dependent manner at 24 h of treatment. Further studies showed that CC treatment induced apoptosis, inhibited Akt/mTOR and signal transducers and activators of transcription protein 3 (STAT3) signaling, altered proteins associated with cell cycle regulation and DNA damage and inhibited colony forming efficiency of HNSCC cells. In addition, CC displayed anti-proliferative activity against a variety of non-HNSCC cell lines of diverse origin. The ability of CC to serve as a dual-inhibitor of Akt/mTOR and STAT3 signaling warrants further studies into its role as a therapeutic strategy against HNSCC.

(6)-Gingerolinduced myeloid leukemia cell death is initiated by reactive oxygen species and activation of miR-27b expression

The natural polyphenolic alkanone (6)-gingerol (6G) has established anti-inflammatory and antitumoral properties. However, its precise mechanism of action in myeloid leukemia cells is unclear. In this study, we investigated the effects of 6G on myeloid leukemia cells in vitro and in vivo. The results of this study showed that 6G inhibited proliferation of myeloid leukemia cell lines and primary myeloid leukemia cells while sparing the normal peripheral blood mononuclear cells, in a concentration- and time-dependent manner. Mechanistic studies using U937 and K562 cell lines revealed that 6G treatment induced reactive oxygen species (ROS) generation by inhibiting mitochondrial respiratory complex I (MRC I), which in turn increased the expression of the oxidative stress response-associated microRNA miR-27b and DNA damage. Elevated miR-27b expression inhibited PPARγ, with subsequent inhibition of the inflammatory cytokine gene expression associated with the oncogenic NF-κB pathway, whereas the increased DNA damage led to G2/M cell cycle arrest. The 6G induced effects were abolished in the presence of anti-miR-27b or the ROS scavenger N-acetylcysteine. In addition, the results of the in vivo xenograft experiments in mice indicated that 6G treatment inhibited tumor cell proliferation and induced apoptosis, in agreement with the in vitro studies. Our data provide new evidence that 6G-induced myeloid leukemia cell death is initiated by reactive oxygen species and mediated through an increase in miR-27b expression and DNA damage. The dual induction of increased miR-27b expression and DNA damage-associated cell cycle arrest by 6G may have implications for myeloid leukemia treatment.

Shikonin selectively induces apoptosis in human prostate cancer cells through the endoplasmic reticulum stress and mitochondrial apoptotic pathway.

BackgroundDespite the recent progress in screening and therapy, a majority of prostate cancer cases eventually attain hormone refractory and chemo-resistant attributes. Conventional chemotherapeutic strategies are effective at very high doses for only palliative management of these prostate cancers. Therefore chemo-sensitization of prostate cancer cells could be a promising strategy for increasing efficacy of the conventional chemotherapeutic agents in prostate cancer patients. Recent studies have indicated that the chemo-preventive natural agents restore the pro-apoptotic protein expression and induce endoplasmic reticulum stress (ER stress) leading to the inhibition of cellular proliferation and activation of the mitochondrial apoptosis in prostate cancer cells. Therefore reprogramming ER stress-mitochondrial dependent apoptosis could be a potential approach for management of hormone refractory chemoresistant prostate cancers. We aimed to study the effects of the natural naphthoquinone Shikonin in human prostate cancer cells.ResultsThe results indicated that Shikonin induces apoptosis in prostate cancer cells through the dual induction of the endoplasmic reticulum stress and mitochondrial dysfunction. Shikonin induced ROS generation and activated ER stress and calpain activity. Moreover, addition of antioxidants attenuated these effects. Shikonin also induced the mitochondrial apoptotic pathway mediated through the enhanced expression of the pro-apoptotic Bax and inhibition of Bcl-2, disruption of the mitochondrial membrane potential (MMP) followed by the activation of caspase-9, caspase-3, and PARP cleavage.ConclusionThe results suggest that shikonin could be useful in the therapeutic management of hormone refractory prostate cancers due to its modulation of the pro-apoptotic ER stress and mitochondrial apoptotic pathways.

Overexpression of COX-2 in oral squamous cell carcinoma patients undergoing chemoradiotherapy.

Aims and Objectives: To evaluate the prognostic significance of cyclooxygenase-2 (COX-2) overexpression in oral squamous cell carcinoma (OSCC) patients undergoing chemoradiation therapy. Purpose of the study was to determine whether COX-2 could be used as a diagnostic and prognostic index in OSCC. Materials and Methods: Forty-four patients of SCC were included in the present study and immunohistochemical examination was done for COX-2 expression. Negative and <5% COX-2 positivity were taken as negative expression and ≥5% COX-2 positivity as positive expression group. ≥30% COX-2 positivity was taken as overexpressed group and <30% COX-2 positivity was taken as underexpressed group. All the data were analyzed statistically. Results: COX-2 overexpression in OSCC was found in 15.90% cases. The proportion of COX-2 overexpression was higher in patients with large tumor size than in those with small tumor size. The proportions of COX-2 positive expression cases were higher with cervical lymph node metastasis. Negative COX-2 expression was higher in well-differentiated OSCC and positive expression was higher in moderately differentiated tumors. COX-2 underexpressed cases had better response to chemoradiation therapy as compared to cases with overexpressed COX-2. Conclusion: COX-2 expression in OSCC can be used as a prognostic marker. Studies with large sample size and long-term follow-up are required to find out the exact role and prognostic significance of COX-2 expression in OSCC.

Oral metastases from carcinoma of cervix

Metastatic tumours of the oral cavity are uncommon, they may occur in soft tissue as well as in bone in the oropharyngeal region. Owing to its rarity, metastatic tumours of the oral regions are a challenge to diagnose. We report a case of metastasis of the oral cavity, arising from uterine cervix mimicking as mucoepidermoid carcinoma. The metastatic lesions were noticed in the soft tissue of the lower buccal and gingival side of a oral cavity, in a 40-year-old woman with history of an adenosquamous carcinoma of uterine cervix treated by panhysterectomy.

Understanding molecular markers in recurrent oral squamous cell carcinoma treated with chemoradiation

Introduction Oral cancer accounts for approximately 2.1% of all cancers worldwide. In India, oral squamous cell carcinoma (OSCC) is the most common cancer with half a million new cases diagnosed every year. More than 50% of patients eventually develop local recurrence or metastasis usually within the first 2-years following completion of treatment. It is beneficial to analyze the prognostic significance of Cyclin D1, p53 and EGFR which are critical mediators in the pathogenesis of OSCC. The objective of this study was to assess the association of expression of these markers with recurrence and pattern of recurrence in OSCC patients undergoing chemoradiation. Materials and Methods A Total 290 OSCC cases of locally advanced stage (III, IV) oral cancer with World Health Organization (W.H.O.) performance status of grade 0/1 in the year 2009–2012 were enrolled in the study. Treatment response was assessed according to W.H.O. criteria. Cyclin D1, EGFR and p53 expression in tumor tissue was estimated by immunohistochemical (IHC) method and quantified as percentage positive nuclei. Results During the 2-years follow up, 56 (19.3%) patients recurred, out of which, 47 (83.9%) were locoregional and 9 (16.1%) distant sites. On correlating, χ2 test showed significant (P < 0.05 or P < 0.01 or P < 0.001) association of marker expressions (Cyclin D1, EGFR and p53) with recurrence. The strong positive expressions of all three markers showed significant association with early time of recurrence. The multivariate logistic regression analysis showed significant (P < 0.05 or P < 0.01 or P < 0.001) association of recurrence with primary site, differentiation, Cyclin D1 and p53 expressions indicating these as an independent predictors of recurrence in OSCC. The Cyclin D1, EGFR and p53 expressions also showed significant (P < 0.001) poor survivals (OS, DFS and RFS) in patients with positive/strong positive expressions than negative expression suggesting their prognosis in OSCC. Conclusion Our results signifies that tumors over expressing Cyclin D1, EGFR and p53 are resistant to chemoradiation and are associated with increased risk of locoregional recurrence and metastasis in OSCC patients undergoing chemoradiation.

Impact of EGFR and p53 expressions on survival and quality of life in locally advanced oral squamous cell carcinoma patients treated with chemoradiation

EGFR and p53 are molecular markers which play important role in tumor progression and development. The objective of this study was to assess the association between EGFR and p53 expression and survival, and to determine whether EGFR and p53 expression levels were associated with differences quality of life in OSCC patients undergoing chemoradiation. A total of 120 OSCC patients aged 20–67 y and stage III/IV were recruited. Treatment response was assessed according to W.H.O. (1979). EGFR and p53 expression in tumor tissue was estimated by immunohistochemical (IHC) method and quantified as percentage positive nuclei. Molecular marker expressions of both EGFR and p53 were found significantly (P < 0.01 or P < 0.001) associated with overall response, survivals and quality of life. Neither EGFR nor p53 expression was associated with hematologic or non-hematologic toxicity. EGFR and p53 molecular marker expressions may have significant association with survival and QOL in OSCC patients undergoing chemoradiation.

Deep vein and artery thrombosis associated with cetuximab-based chemoradiotherapy

Molecular targeted agents have lower hematological toxicity. However, specific side-effects such as allergic rashes, skin reactions and high cost limit their use. We report a case of 35-year-old male patient with carcinoma of left tonsil treated with concurrent cetuximab and radiotherapy. After four weeks of treatment, the patient developed sudden onset of pain in the left calf region radiating to the left foot. Doppler study of the left lower limb revealed complete thrombosis of superficial femoral, popliteal and proximal tibial arteries and veins and no flow in anterior tibial artery and lower posterior tibial artery. Emergency embolectomy was done. After 48 h of observation, no improvement was noted. A repeat Doppler examination showed similar finding. Ultimately a left lower limb amputation was done. We report simultaneous arterio-venous thrombosis associated with cetuximab-based chemoradiotherapy. Oncologists should be aware of this possible complication to undertake early intervention.

Exploring new potentials and generating hypothesis for management of locally advanced head neck cancer: Analysis of pooled data from two phase II trials

BACKGROUND To study the long term results of two phase II concurrent chemoradiotherapy protocols and conduct pooled data analysis with special emphasis on nodal density. MATERIALS AND METHODS In the period from April 2001 to May 2003, phase II Mitomycin C (MMC) and late chemo-intensification (LCI) protocols were started in the same institute, enrolling 69 and 74 patients respectively. Long term results for these individual trials are reported along with pooled data analysis. RESULTS Median follow-up time for whole group, MMC protocol and LCI protocol was 43.8 months (SD619.8), 55 months (SD 618.5) and 47.5 months (SD 620.9) respectively. LRFS, DFS and OS at five years for whole group was 59.4, 43.5 and 47.1% respectively, for MMC protocol was 59.9, 45.5 and 49.5% respectively and for LCI, protocol was 53.6%, 41.5% and 44.4% respectively. Subgroup analysis revealed that MMC protocol was more effective than LCI protocol in terms of DFS and OS in patients with hypo dense nodes while opposite was true for Isodense nodes. Multivariate analysis revealed nodal density as an independent variable that had an impact on treatment outcome. Risk of death in patients with hypo dense nodes was 2.91 times that of Isodense nodes. CONCLUSIONS Innovative and pragmatic approach is required to address locally advanced head neck cancer. Long term results for MMC and LCI protocols are encouraging. Integrating the basic concepts of these protocols may help develop new protocols, which will facilitate the search for the optimal solution.