title: Basal cell carcinoma.
abstract: BACKGROUND
  Basal cell carcinoma (BCC) is characterized by marked interpatient variation in tumor accrual. The authors previously reported that presentation with a cluster of BCC is associated with an inherited predisposition to develop many additional lesions suggesting clustering is a critical event. A cluster is defined as the presence of two or more new, primary BCCs, at initial or later presentation.
  
  
  METHODS
  The authors recruited 927 cases and determined whether 1) clustering was an early or late event and 2) tumor accrual was altered after clustering.
  
  
  RESULTS
  In the cases, 669 patients developed only 1 lesion, 112 patients presented more than once but with single lesions (single presentation phenotype[SPP]-more), 94 cases had a cluster at first presentation (multiple presentation phenotype [MPP]-cluster initial), and 52 cases first presented with 1 lesion but later had a cluster (MPP-cluster later). The authors found that 1) clustering occurred relatively late. The mean ages at first presentation with 1 BCC of the SPP-more (61.5 years) and MPP-cluster later patients (60.4 years) were similar although presentations with clusters in the MPP-cluster initial (67.6 years, P = 0.0002) and -cluster later cases (68.1 years, P = 0.002) occurred significantly later. 2) Clustering was associated with increased accrual. Thus, 26 patients (MPP-cluster later/a) in the MPP-cluster later group had a additional BCC postcluster. Mean accrual post-cluster (1.99 BCC/year) in these cases was significantly increased (P = 0.0001) compared with precluster accrual (0.39 BCC/year).
  
  
  CONCLUSIONS
  The authors found that the formation of BCC clusters represents a critical event such that after a cluster presentation, tumor accrual is significantly increased. Cluster presentation is a relatively late event suggesting reduced effectiveness in immune surveillance.
authors.affiliation: Centre for Cell and Molecular Medicine, School of Postgraduate Medicine, North Staffordshire Hospital, Keele University, Staffordshire, England.
authors.forename: S
authors.initials: S
authors.lastname: Ramachandran
authors.forename: A A
authors.initials: AA
authors.lastname: Fryer
authors.forename: A G
authors.initials: AG
authors.lastname: Smith
authors.forename: J T
authors.initials: JT
authors.lastname: Lear
authors.forename: B
authors.initials: B
authors.lastname: Bowers
authors.forename: C E
authors.initials: CE
authors.lastname: Griffiths
authors.forename: P W
authors.initials: PW
authors.lastname: Jones
authors.forename: R C
authors.initials: RC
authors.lastname: Strange
mesh_terms: D000367:Age Factors; D000368:Aged; D002280:Basal Cell Carcinoma / Q000145:classification / Q000453:epidemiology / Q000235:genetics / Q000503:physiopathology*; D003627:Data Interpretation, Statistical; D020022:Genetic Predisposition to Disease; D006801:Humans; D008875:Middle Aged; D008954:Models, Biological; D009378:Neoplasms, Multiple Primary / Q000453:epidemiology / Q000209:etiology*; D010641:Phenotype; D012878:Skin Neoplasms / Q000145:classification / Q000453:epidemiology / Q000235:genetics / Q000503:physiopathology*