title: Evaluation of the Role of ALDH1 as Cancer Stem Cell Marker in Colorectal Carcinoma: An Immunohistochemical Study.
abstract: BACKGROUND
  Colorectal Carcinoma (CRC) is the third most commonly diagnosed cancer in males. Stem Cells (SC) may be involved in tumour growth, including colon cancer. Aldehyde Dehydrogenase 1 (ALDH1) is a detoxifying enzyme that might modulate SC proliferation.
  
  
  OBJECTIVE
  To evaluate the immunohistochemical expression of ALDH1 as stem cell marker in the pathogenesis of colorectal carcinoma.
  
  
  METHODS
  This retrospective study included 71 colorectal specimens (49 colorectal carcinoma, 13 adenoma and 9 normal cases) that were collected from Pathology Department, Faculty of Medicine, Menoufia University during the period from 2011 to 2015. All cases were stained by ALDH 1 antibody. Survival data were available for 31cases.
  
  
  RESULTS
  There was a statistical significant association between epithelial positivity of ALDH1 and younger age (p=0.003), right sided tumour (p=0.038), presence of lymph node invasion (p= 0.04), ulcerating gross picture (p=0.01) and presence of vascular invasion (p=0.05). Moreover, there was statistical significant association between stromal positivity of ALDH1 and smaller tumour size (p=0.03) and inverse association between stromal expression of ALDH1 and grade of tumour (p=0.000) and perineural invasion (p= 0.05). Furthermore, there was an inverse significant relation between CD44 and ALDH1 expression (p=0.001). Univariate recurrence free survival analysis revealed the bad prognostic impact of high grade (p=0.03) and female sex (p=0.02) on patient outcome.
  
  
  CONCLUSIONS
  Epithelial expression of ALDH1 might be associated with poor prognosis while its stromal expression might be associated with good prognosis.
authors.affiliation: Department of Pathology, Faculty of Medicine, Menoufia University , Shebien ElKom, Menoufia, Egypt .
authors.forename: Nanis Shawky
authors.initials: NS
authors.lastname: Holah
authors.affiliation: Professor, Department of Pathology, Faculty of Medicine, Menoufia University , Shebien ElKom, Menoufia, Egypt .
authors.forename: Hayam Abd-El-Samie
authors.initials: HA
authors.lastname: Aiad
authors.affiliation: Professor, Department of Pathology, Faculty of Medicine, Menoufia University , Shebien ElKom, Menoufia, Egypt .
authors.forename: Nancy Yousif
authors.initials: NY
authors.lastname: Asaad
authors.affiliation: Department of Oncology, Faculty of Medicine, Menoufia University , Shebien ElKom, Menoufia, Egypt .
authors.forename: Enas Abobakr
authors.initials: EA
authors.lastname: Elkhouly
authors.affiliation: Department of Pathology, Faculty of Medicine, Menoufia University , Shebien ElKom, Menoufia, Egypt .
authors.forename: Ayat Gamal
authors.initials: AG
authors.lastname: Lasheen
keywords: Lymphovascular invasion; Rabbit polyclonal antibody; Streptavidin-biotin amplified system