Latest Research News on Malignant Tumor : Nov 2020
Metastasis results from preexisting variant cells within a malignant tumor
Clones derived in vitro from a parent culture of murine malignant melanoma cells varied greatly in their ability to produce metastatic colonies in the lungs upon intravenous inoculation into syngeneic mice. This suggests that the parent tumor is heterogeneous and that highly metastatic tumor cell variants preexist in the parental population. 
Method for determining if a tissue is a malignant tumor tissue, a benign tumor tissue, or a normal or benign tissue using Raman spectroscopy
A method for determining if a tissue is a malignant tumor tissue, a benign tumor tissue, or a normal or benign tissue. The present method is based on the discovery that, when irradiated with a beam of infrared, monochromatic light, malignant tumor tissue, benign tumor tissue, and normal or benign tissue produce distinguishable Raman spectra. For human breast tissue, some salient differences in the respective Raman spectra are the presence of four Raman bands at a Raman shift of about 1078, 1300, 1445, and 1651 cm-1 for normal or benign tissue, the presence of three Raman bands at a Raman shift of about 1240, 1445, and 1659 cm-1 for benign tumor tissue, and the presence of two Raman bands at a Raman shift of about 1445 and 1651 cm-1 for malignant tumor tissue. In addition, it was discovered that for human breast tissue the ratio of intensities of the Raman bands at a Raman shift of about 1445 and 1659 cm-1 is about 1.25 for normal or benign tissue, about 0.93 for benign tumor tissue, and about 0.87 for malignant tumor tissue. 
Abnormal regulation of mammalian p21ras contributes to malignant tumor growth in von Recklinghausen (type 1) neurofibromatosis
Tumor cell lines derived from malignant schwannomas removed from patients with neurofibromatosis type 1 (NF1) have been examined for the level of expression of NF1 protein. All three NF1 lines examined expressed lower levels of NF1 protein than control cells, and the level in one line was barely detectable. The tumor lines expressed normal levels of p120 GAP and p21 ras. Although the p21 ras proteins isolated from the tumor cells had normal (nonmutant) biochemical properties in vitro, they displayed elevated levels of bound GTP in vivo. The level of total cellular GAP-like activity was reduced in extracts from the tumor line that expresses very little NF1 protein. Introduction of the catalytic region of GAP into this line resulted in morphological reversion and lower in vivo GTP binding by endogenous p21 ras. These data implicate NF1 protein as a tumor suppressor gene product that negatively regulates p21 ras and define a “positive” growth role for ras activity in NF1 malignancies. 
Histopathological Pattern of Pediatric Malignant Tumors and Survival Rate at Kilimanjaro Christian Medical Centre, Tanzania from 2013 to 2015
Background: Childhood malignant tumors are among diseases that cause death to children below 14 years. Although it is the second most common cause of death in children in developed countries, its magnitude in Africa is not well known.
Aim: To determine the proportion of pediatric malignant tumors and the immediate outcome among children attending Kilimanjaro Christian Medical Centre in Tanzania.
Study Design: Retrospective – hospital based study.
Place and Duration: Kilimanjaro Christian Medical Centre, Pathology department, 3 years.
Methodology: Microscopic slides from January 2013 to December 2015 were retrieved from archives and evaluated at a magnification of 40x, 100x and 200x for histological features, diagnosis and disease grading. The findings were confirmed by the pediatric pathologist and concluded on the diagnoses and the grade. The tumors were graded into well-differentiated and undifferentiated. Parents/guardians were contacted through phone calls to establish progress of their children to assess the six-month survival rate.
Results: Among 84 studied patients’ slides, 43 (51.2%) were from males with the median (IQR) age of 4.5 (2.3-9.3) years while 50 children (59.5%) were under five years of age. Retinoblastoma 21 (25%) was the most common malignant tumor followed by Squamous cell carcinoma and Sarcoma comprising 13 (15.5%) each. Among 75 children other than patients with leukemia, 42 (56.0%) had well differentiated and 33 (44.0%) had undifferentiated malignant tumors. Forty-one (97.6%) of the patients with well-differentiated malignant tumors survived within six months from the date the specimen was taken. The overall six-month survival rate was 84.5%. Thirteen patients (15.5%) died during the six-month period of follow up.
Conclusion: Retinoblastoma was the most common malignant tumor affecting children <14 years in northern Tanzania. The overall six-month survival rate was high when early detection of childhood malignancies is practicable. 
Malignant Retroperitoneal Extra-Gastrointestinal Stromal Tumor: A Case Report
Context: Extragastrointestinal stromal tumors (EGIST) are extremely uncommon neoplasm. To the best of our knowledge, only one retroperitoneal EGIST case has been reported in Oncolgy, in 2005ï¼ˆPubMed search result).
Case Report: A 67-year old female patient presented with epigastric discomfort, dyspepsia, and anemia. Ultrasonographic examination of the abdomen showed the location of the tumor was between the tail of the pancreas and the spleen (retroperitoneal), it was variable in size of 12.3cm×7.2cm×14cm. Color Doppler Flow Imaging (CDFI) showed no flow signals with arterial-venous doppler spectrum in the massesï¼ŽContrast-enhanced computed tomography of the abdomen revealed a heterogeneously enhancing mass (8.23cm×14.2cm) and abundant blood supply of the tumor. The patient underwent gastroscopes-guided biopsy from the fundus of stomach for pathologic diagnosis and the result indicated chronic superficial gastritis. A complete gross excision was performed. Retroperitoneal tylectomy, left hepatic lobectomy, enterolysis, and liver biopsy were performed. Two weeks post operation, the patient was discharged without any postoperative problems. The final diagnosis of retroperitoneal EGIST was confirmed by histopathological examination and immunohistochemical findings (CD117 positivity).
Conclusion: We report a very rare case of retroperitoneal EGIST. Although the Ultrasonographic examination, computer tomography and endoscopy examination did not confirm the final diagnosis, they are complemented to each other in order to identify the exact location of the tumor. EGIST should be considered in the differential diagnosis of solid masses of abdomen on cytology and immunohistology. 
 Fidler, I.J. and Kripke, M.L., 1977. Metastasis results from preexisting variant cells within a malignant tumor. Science, 197(4306), pp.893-895.
 Alfano, R.R., Liu, C.H. and Glassman, W.S., Alfano Robert R, Liu Cheng H and Glassman Wenling S, 1993. Method for determining if a tissue is a malignant tumor tissue, a benign tumor tissue, or a normal or benign tissue using Raman spectroscopy. U.S. Patent 5,261,410.
 DeClue, J.E., Papageorge, A.G., Fletcher, J.A., Diehl, S.R., Ratner, N., Vass, W.C. and Lowy, D.R., 1992. Abnormal regulation of mammalian p21ras contributes to malignant tumor growth in von Recklinghausen (type 1) neurofibromatosis. Cell, 69(2), pp.265-273.
 Killenga, S., Msuya, S., Philemon, R., Mremi, A. and T. Mmbaga, B. (2016) “Histopathological Pattern of Pediatric Malignant Tumors and Survival Rate at Kilimanjaro Christian Medical Centre, Tanzania from 2013 to 2015”, Journal of Cancer and Tumor International, 4(2), pp. 1-8. doi: 10.9734/JCTI/2016/29031.
 Abuduwayite, R., Muhemaiti, A., Biekemituofu, H. and Mohemaiti, P. (2012) “Malignant Retroperitoneal Extra-Gastrointestinal Stromal Tumor: A Case Report”, Journal of Advances in Medicine and Medical Research, 2(2), pp. 142-149. doi: 10.9734/BJMMR/2012/832.