This coursework comprises of questions covering statistical analysis of research data. Some of these questions have multiple parts.
Answer all of the questions clearly so that your final answer is obvious.
Provide your answers in the most appropriate format (e.g. M, mM, μM, kg, mg etc) and to two decimal places.
You will be expected to provide graphs for some of the statistical analysis questions. Ensure that these are clearly presented and in the correct format for submission (i.e. use an excel sheet or paste this into a word/pdf file). It is your responsibility to check that the graphs are formatted correctly before submission.
1. You have conducted IHC (immunohistochemistry) staining of nuclear ß-catenin in triple-negative breast cancer cells (MDA231 cells) following treatment with ‘WTX’, a WNT pathway inhibitor.
The has been performed in triplicate with representative IHC images shown below:
(A=Control; B=0.1µM WTX; C=1µM WTX; D=10µM WTX)
H-Score analysis of ß-catenin expression are as follows:
|
|
[WTX] µM |
0 |
0.1 |
1 |
10 |
|
|
|
|
|
|
|
|
H-Scores |
Sample set 1 |
287 |
255 |
124 |
76 |
|
Sample set 2 |
277 |
274 |
141 |
55 |
|
|
Sample set 3 |
242 |
268 |
89 |
48 |
(i) Calculate the mean H-Score and standard error for each concentration of WTX [2 marks]
(ii) Plot this data on a graph using an appropriate style. Include an appropriate legend [2 marks]
(iii) Apply the correct statistical test to your data in order to determine whether any of the WTX treatments produced statistically significant effects [2 marks]
2. The IHC experiment in (A) above was repeated for a breast cancer cell line that was ER+ (MCF7 cells) and the following data obtained:
|
|
[WTX] µM |
0 |
0.1 |
1 |
10 |
|
|
|
|
|
|
|
|
H-Scores |
Sample set 1 |
144 |
136 |
133 |
97 |
|
Sample set 2 |
135 |
117 |
138 |
107 |
|
|
Sample set 3 |
108 |
154 |
129 |
104 |
(i) Perform the relevant calculations and plot a graph that enables you to directly compare the effects of WTX on MDA231 and MCF7 cells. [5 marks]
(ii) Apply the correct statistical test to your data to determine if there are significant differences between the effects of WTX on MCF7 and MCD231 cells [4 marks]
3. An experiment was conducted to compare the effects of a novel EGFR inhibitor (SPC71) on the growth of two pancreatic cell lines.
The data from three independent experiments are shown for both cell lines in the tables below.
Assume that absorbance is directly related to cell number (i.e. the greater the absorbance, the more cells there are in the well).
Cell line: Panc1
Growth data (absorbance values)
|
|
[SPC71] (μM) |
0 |
0.0001 |
0.001 |
0.01 |
0.1 |
1 |
5 |
|
Experiment 1 absorbance values |
0.999 |
0.815 |
0.793 |
0.962 |
0.826 |
0.747 |
0.304 |
|
|
Experiment 2 absorbance values |
0.924 |
0.772 |
0.799 |
0.963 |
0.785 |
0.721 |
0.174 |
|
|
Experiment 3 absorbance values |
0.697 |
0.758 |
0.794 |
0.828 |
0.842 |
0.697 |
0.293 |
|
Cell line: MiaPaca2
Growth date (absorbance values)
|
|
[SPC71] (μM) |
0 |
0.0001 |
0.001 |
0.01 |
0.1 |
1 |
5 |
|
Experiment 1 absorbance values |
0.559 |
0.538 |
0.561 |
0.524 |
0.32 |
0.178 |
0.177 |
|
|
Experiment 2 absorbance values |
0.573 |
0.571 |
0.571 |
0.573 |
0.36 |
0.162 |
0.164 |
|
|
Experiment 3 absorbance values |
0.55 |
0.543 |
0.564 |
0.524 |
0.30 |
0.175 |
0.148 |
|
Process the data above in an appropriate way so that you are able to determine:
(i) Whether the effects of SPC71 significantly suppress proliferation of either cell line [5 marks]
(ii) Whether there is a differential sensitivity to SPC71 between the two cell lies tested and whether this is significant and, if so, at what concentration [5 marks]
In your answer you will be expected to use appropriate statistical testing and plot your data in an appropriate manner.
4. A clinical trial was set up to determine whether adding a BRK inhibitor to chemotherapy improved stage IV melanoma patient survival versus patients receiving chemotherapy only.