Nanoscale cellular changes in field carcinogenesis detected by partial wave spectroscopy

Abstract

Understanding alteration of cell morphology in disease has been hampered by the diffraction-limited resolution of optical microscopy (>200 nm). We recently developed an optical microscopy technique, partial wave spectroscopy (PWS), which is capable of quantifying statistical properties of cell structure at the nanoscale. Here we use PWS to show for the first time the increase in the disorder strength of the nanoscale architecture not only in tumor cells but also in the microscopically normal-appearing cells outside of the tumor. Although genetic and epigenetic alterations have been previously observed in the field of carcinogenesis, these cells were considered morphologically normal. Our data show organ-wide alteration in cell nanoarchitecture. This seems to be a general event in carcinogenesis, which is supported by our data in three types of cancer: colon, pancreatic, and lung. These results have important implications in that PWS can be used as a new method to identify patients harboring malignant or premalignant tumors by interrogating easily accessible tissue sites distant from the location of the lesion.

Figure 1

(a) Cells at a distance from a colon tumor undergo changes in their internal nanoarchitecture similar to tumor cells. The values of L_d and its intracellular standard deviation σ_Ld averaged over a cell, that is $L_d^{(c)}$ and σ^(c), for control cells, tumor cells, and cells at a 4 cm distance from tumor plotted in $L_d^{(c)}$, σ^(c) parameter space. Each point in this diagram corresponds to a single cell. As can be seen, the histologically normal cells at a distance from a tumor have an increased disorder strength due to field carcinogenesis. (b) The relative values of the disorder strength $L_d^{(d)}$ for the control cells, tumor cells and cells away from tumor. $L_d^{(g)}$ is obtained by averaging $L_d^{(c)}$ from randomly chosen ~30 cells for each of the three cell types. The error bar represents the standard error of the mean. The average disorder strength $L_d^{(g)}$ is significantly increased in the tumor cells compare to control cells (Student t-test p-value <0.0001). More importantly, cells 4 cm away from tumor also undergo increased disorder strength compared to control (p-value < 0.0001). (c) The values of the intracellular standard deviation of the disorder strength σ^(g) for the three cell types. σ^(g) is obtained from ~30 cells for each cell types. The error bars represent the standard errors of the means. σ^(g) is progressively increased in cells 4 cm away from tumor to the tumor cells compared to control (all p-values < 0.0001).

Figure 2

Cells obtained from histologically normal colonic mucosa have increased disorder strength due to the presence of premalignant tumors anywhere else in colon. (a) The values $L_d^{(c)}$ and σ^(c) obtained from histologically normal rectal mucosa from control patients and those with adenomatous polyp elsewhere in the colon. Though histologically normal, the rectal cells from patients with premalignant tumors occupy a separate regime in the parameter space with only slight overlap with the normal cells. (b) The relative values of the disorder strength $L_d^{(g)}$ for cells from histologically normal rectal mucosa in patients with premalignant tumors and those with no tumors present. The average disorder strength $L_d^{(g)}$ is significantly elevated in cells from patients with presence of adenomatous polyps elsewhere in the colon compared to controls (p-value <0.0001). (c) The relative values of intracellular standard deviation of the disorder strength σ^(g) from histologically normal rectal mucosa. σ^(g) is obtained from ~30 cells for each cell types. The error bars represent the standard errors of the means. Similar to $L_d^{(g)}$, the σ^(g) is significantly elevated in patients with the presence of premalignant tumors elsewhere in colon (p-values < 0.0001).

Figure 3

(a) Histologically normal duodenal mucosa cells have increased disorder strength due to the presence of pancreatic cancer. The $L_d^{(c)}$ and σ^(c) obtained from histologically normal duodenal mucosa from patients with pancreatic cancer and with no cancer. Though histologically normal, the $L_d^{(c)}$ and σ^(c) from the duodenal cells are significantly elevated in patients with pancreatic cancer (p-value < 0.0001) and the values only slightly overlap with the cells from control patients. (b) Cells obtained from histologically normal buccal mucosa have increased disorder strength due to the presence of lung cancer. The values of $L_d^{(c)}$ and σ^(c) obtained from histologically normal buccal mucosa from patients with chronic obstructive pulmonary disease COPD and those with lung cancer. Though histologically normal, the buccal mucosa cells have a much higher $L_d^{(c)}$ and σ^(c) in patients with lung cancer compared to those patients with COPD (p-value < 0.0001).