Are Gastric Cancer Resection Margin Proteomic Profiles More Similar to Those from Controls or Tumors?

A strategy for treating cancer is to surgically remove
the tumor together with a portion of apparently healthy tissue surrounding
it, the so-called “resection margin”, to minimize recurrence.
Here, we investigate whether the proteomic profiles from biopsies
of gastric cancer resection margins are indeed more similar to those
from healthy tissue than from cancer biopsies. To this end, we analyzed
biopsies using an offline MudPIT shotgun proteomic approach and performed
label-free quantitation through a distributed normalized spectral
abundance factor approach adapted for extracted ion chromatograms
(XICs). A multidimensional scaling analysis revealed that each of
those tissue-types is very distinct from each other. The resection
margin presented several proteins previously correlated with cancer,
but also other overexpressed proteins that may be related to tumor
nourishment and metastasis, such as collagen alpha-1, ceruloplasmin,
calpastatin, and E-cadherin. We argue that the resection margin plays
a key role in Paget’s “soil to seed” hypothesis,
that is, that cancer cells require a special microenvironment to nourish
and that understanding it could ultimately lead to more effective
treatments.