Background: Colorectal cancer is one of the leading causes of cancer death in both developed and developing nations. It is the third most common type of cancer and the second leading cause of cancer death in the Unites State.

Material & Methods: The current study included sixty cases of colorectal carcinomas studied histologically and immunohistochemically for WT1 expression.

Abstract The fast and nearly non-destructive criteria of laser induced breakdown spectroscopy (LIBS) technique has been exploited for forensic purposes, specifically, document investigation. The dependence of the optical emission spectra of different black gel ink samples on the excitation laser wavelength, namely the visible wavelength at λ = 532 nm and the İR\} wavelength at λ = 1064 nm, was studied. The inks of thirty black gel-ink pens comprising ten brands were analyzed to determine the variation of the chemical composition of ink and to discriminate among them with minimum mass removal and minimum damage to the document's paper. Under the adopted experimental conditions, the ability of the visible \{LIBS\} to differentiate among the different ink samples was successful compared to İR\} \{LIBS\} at the same laser pulse energy (  25 mJ/pulse, laser fluence is   1400 J·cm- 2 for visible laser and   1100 J·cm− 2 for İR\} laser) which could be attributed to the İR\} absorption effects by the black ink. However, the visible \{LIBS\} produces deeper crater with respect to that produced by İR\} LIBS. Applying İR\} \{LIBS\} with higher pulse energy of   87 mJ (laser fluence is   4100 J·cm− 2), identification and differentiation of the adopted samples was performed with producing a larger-diameter but superficial crater. The plasma parameters are discussed at the adopted experimental conditions. The results support the potential of \{LIBS\} technique using both the visible and İR\} lasers to be commercially developed for forensic document examination.